> what does labor get when there are temporarily low or negative profits?
good question - the current system ensures that labour gets paid, regardless of profits being negative or not (until the company collapses). This is enshrined into law - you cannot leave wages unpaid, and it sits above creditors in seniority.
If they gave 100% of their profits to the workers as the only pay, then long term workers could presumably self-insure.
It looks like excellent solution for startup: just pay 100% of startup profit to workers by giving them 100% of shares, so they will self-insure themselves and be OK when startup will fail.
That almost guarantees that fewer companies will be started, since your model removes incentive for people to benefit from starting companies.
The socialist solution is actually centralized planning over multiple industry sectors. The workers would be paid profits from a huge, diversified conglomerate, mot merely the one industry sector that they happened to be working in. Of course, this leads to all the known drawbacks of central planning.
I used to work at a company which gave 10% of its profits to the workers each month as a bonus. But I was only there during some money-losing months so I got zero bonus. Imagine if that had been my entire pay!