I think there is a very convincing story in which the emergence of the modern corporation in the early decades of the 20th century, and then the vast expansion of the federal administrative apparatus in the New Deal and (especially) World War II, created a class of professional managers with substantial autonomy from the notional owners of capital. (Not as cohesive as the enarques in France, but the same kind of stratum.) As managers of firms they pursued a variety of objectives, of which providing a satisfactory (not maximal) flow of payments to shareholders was just one among others.
At some point (in the late 1970s, let's say) this arrangement broke down, with conflicts both between managers and owners over the fraction of surplus flowing to the latter, and between owners and workers, over the size of the surplus, with mangers basically on the side of owners. The second of these conflicts was, in some sense, more fundamental, but the first one was also real and important.
You then had a series of institutional changes that were intended to realign the interests of managers with owners, in terms of both conflicts. During the period of realignment, these changes took the form -- at least at times -- of open conflict, with recalcitrant managers forcibly removed by LBOs, etc. But over time, top management was effectively absorbed into the capitalist class proper, and stopped seeing themselves as the social embodiment of the firm as a social organism or representatives of society as a whole. At the same time, there does have to be continuous policing to ensure that management doesn't deviate from the goal of maximizing payments to shareholders. That is finance's other function, along with intermediation, and it's this second function that has been responsible for finance's growth over the past decades. (Along with the rents that financial institutions and asset-owners claim in the course of doing their enforcement work.)
So in terms of overt conflict between owners and managers, the shareholder revolution is over; the shareholders won. The fly in the ointment is that no one is policing the police, and unlike other institutional supports of the capitalist system (the actual police, say, or the legal profession or academia) they don't have the right internal norms to make them reliable servants.
That's how it looks to me, anyway. I realize this is just a set of assertions, which would need to be backed up with evidence/examples to convince anyone who's not already convinced. As usual, I recommend Doug H.'s Wall Street (especially chapter 6, which I'm having my students read this semester) and Dumenil & Levy's Crisis of Neoliberalism to see the argument developed properly. One of these days maybe I'll write something substantive on it myself.
I should add, an interesting aspect of the counterrevolution of the rentiers is the way that the claim of shareholders on the maximum possible payments from "their" firms has become an accepted moral principle. There are lots of educated people, even liberals, who unquestioningly believe that it is morally wrong for managers to have any objectives except maximizing future dividend payments. E.g. look at this old Baseline Scenario post on Goldman Sachs' relatively low 2009 bonuses, with the unironic title Good for Goldman:
Goldman did the right thing here.We all know that Goldman made a lot of money last year. ... Many people think that it made that money because of government support, but that’s beside the point here; right now, this is purely a question of dividing the spoils between employees and shareholders.
Historically, investment banks have given a large proportion of the profits (here, meaning before compensation and taxes) to the employees. For example, in 2007 Goldman gave $20.2 billion out of $37.8 billion to its employees, or 53%. There are undoubtedly many reasons for this. ... More insidiously, investment banking executives tend to see their employees as younger versions of themselves, which creates a sense of solidarity... Contrast this to, say, Wal-Mart, where top management has very little in common (socially, educationally, economically, politically, etc.) with the vast majority of their employees. As a result, investment bankers are overpaid. ...
Goldman should reduce its per-employee compensation expenses even further, and should try to push the industry to a new equilibrium where the payout ratio is in the 30-40% range and average compensation for investment bankers is in the $300-400,000 range. And Goldman’s shareholders should apply pressure to make this happen; basically, they should try to squeeze labor.I find this sort of thing fascinating. James Kwak is a liberal, one of the good guys. But it's awfully hard not to read him here as saying it's a good thing that Wal-Mart execs have nothing in common with the proles to distract them from serving their true masters, and that where a sense of solidarity does exist between managers and workers, it's an "insidious" problem that needs to be stamped out. There's nothing ironic in those "should"s.
Of course I'm no fan of traders, financial engineers, and the rest of the pirates, but as Kwak himself says, this is "purely a question of dividing the spoils." So I don't see why the silent partners who finance the privateers have any better claim than the guys with flintlocks and cutlasses, or why we should treat it as something to celebrate when the financiers get a bigger share of the take.  What's strange is how many people, many not especially rich or conservative, have been somehow convinced that the biggest problem with businesses is that they aren't run purely enough for profit, and that employees still have too much control over their work and pay. That in any conflict between owners and workers or managers, the social interest is obviously -- obviously -- on the side of the owners. It's nuts.
 Ok, yes, about 15 percent of corporate equity is owned by pension funds. So yes, salaried workers (including me and probably you) do in some sense confront employees, at both Goldman and Wal-Mart, as owners. We can't just say "the capitalist is the personification of capital" and be done with it, as Marx did; capitalist as economic function and capitalists as sociological category don't coincide as nicely as they did in his day. But why should we let our little interest as junior capitalists dominate our much larger interests as workers, citizens, and human beings? Why should we assume that the claims on business exercised by virtue of capital ownership, are the only ones that are morally legitimate?