ISS[0], Vanguard, and other fund families absolutely have massive say (powered by those 401k balances) over corporate conduct.

[0] - https://www.issgovernance.com

Their corporate governance teams are surprisingly small. Vanguard has only something like 35 people overseeing thousands of companies and voting on hundreds of thousands proposals each year.

As a result, some of that voting is running - literally - on autopilot, see https://www.issgovernance.com/solutions/proxy-voting-service... and https://corpgov.law.harvard.edu/2018/11/29/the-realities-of-...

The entire point of having ISS (or Glass Lewis) advise on voting and offer options like autopilot is to give the collective power of all those tiny 401K balances to a single unifying entity who can help drive shareholder-friendly terms (or at least provide a partial balance to what might otherwise become too boardroom-friendly terms). I view that the voting is on autopilot as a potentially positive control not the negative that you seem to believe it to be.

Some fund companies commit to following ISS advice across the board or on certain topics. Others like Vanguard delegate the voting power to fund managers (who have access to ISS reports but aren't obliged to follow it slavishly).

My point was that Vanguard et al have massive power, but they are not using it, e.g. https://www.reuters.com/article/us-usa-funds-index-specialre...

I would expect the overwhelming majority of actively managed funds to vote with management recommendations. If they didn’t agree with management, it’s much quicker and more effective to decline to invest rather than invest and then vote against them.

You don’t need a vote to sell your shares and drive the stock price down, which executives absolutely do care about.