Steel-manning the argument, there is the notion that we could create a functional well-regulated capitalist society that is robust against capture by companies and elites. The problems we haven't solved are twofold:

One, company officials will do what they want rather than what maximizes profit, usually because the shareholders and watchdogs don't always know what maximizes profit in the long term, so they can't demand upper management to do that.

This is why we still have crunching in media development. This it's why we have poor treatment of employees generally. (It's established by data now that crunching doesn't speed the way to meeting deadlines, and well-treated workers produce more value at a rate that exceeds the cost of treating them well in contrast to treating them poorly. Companies treat them like shit anyway.) This is also why we have a lot of bullshit jobs which are office clerks being used and treated more as courtiers and garden hermits than office staff.

And two is that once government is partially captured, it always moves towards getting more captured and serving companies over the public. This is the fundamental failure in the system that Marx defines in Das Kapital.

So far we've not figured out a way to counter these properties of capitalism as practiced worldwide. Should we ever, then regulated capitalism will be a viable economic model, but not yet. This isn't to say a solution doesn't exist, only we haven't found it yet.