Companies survive because they don't die. That seems trite, I know. The consequences of it are important, as the equation is one where no matter how well you do, avoiding death is what matters.
SHL at Gumroad is a great example. SHL was encouraged to quit by the VCs when Gumroad was not a clear unicorn[1]. SHL chose not to let Gumroad die, and Gumroad lives.
The problem with all the ideas like the one Yanis Varoufakis proposes, is that they will almost certainly do well in good times, but companies survive because they don't die, and any system like the one you mention will lead to more dead companies.
That's a big claim I know, but imagine a situation where a company has 20 people - 4 sales and 8 support (secretaries, returns, admin) in the office and 8 people who work in fulfillment - a warehouse and lets say deliveries. Times get tough, and they are forced to have a vote on who needs to be sacked - how do they vote? 12 of the 20 work together, do you really think they will vote to have their friends in the office sacked?
And would they even get to that point? Why would anyone ever vote to lose their job? And what about pay rises? How do you negotiate pay rises when everyone votes? In a multi-division company, lets say 3 divisions, would everyone vote to take a lower pay than people in a more productive division? Would hiring be run along profitability lines, with one division growing large, or prestige/some other political goal like maintaining voting block power?
Capital has clearly aligned goals that round to "don't die". Capital will be assigned in productive areas, pay rates will be higher in more valuable divisions (AWS vs Amazon Warehouse workers) and kill off products that aren't working (See Google).
At the meta, system level, there is also alignment. Capital can be reassigned to different companies, aligning the individual players with the system overall. That is why Blackberry was valued below its cash on hand at one point - capital was reassigned as Blackberry was more likely to blow through the cash than grow. A system where shares can not be reassigned has no system level optimisation which saves the system, even as individual companies die.
The same is not self evidently obvious or clear in collectivist systems, and always needs a series of extra steps to overcome self interest to be possible, none of which are convincing over longer timeframes.
Any collectivist system would only need a very small bias towards something other than optimising profitability to have long term terrible consequences. Homo Sapiens had a tiny advantage over Neanderthals and other Hominids, and we are here and they are not. The casino advantage in most games is < 3% and think how much money they make.
Collectivist business ideas will have all the same problems of politics, combined with the ability to die completely, which Governments do not suffer outside of war, as they have a taxation monopoly.
[1] https://sahillavingia.com/reflecting - "Some of my investors wanted me to shut down the business. They tried to convince me that my time was worth more than trying to keep a small business like Gumroad afloat, and I should try to build another billion-dollar company armed with all of my learnings — and their money."