> some regional tender processes have gotten even worse, where the state prescribes or outright buys the rolling stock

Isn't this done in an attempt to resolve some of the issues you mentioned?

If you don't want the absolute cheapest old run-down toilet-less rolling stock, the tender has to be quite specific about the minimum requirements the rolling stock is expected to meet. This in turn means an operator switch leaves the new operator having to quickly obtain a bunch of highly-specific rolling stock with the old operator having to get rid of a bunch of now-worthless highly-specific rolling stock.

The logical result is that the old operator sells the rolling stock to the new operator. Or, you have the rolling stock owned by a holding company, who leases it to whoever happens to be operating the tender. Same with the maintenance shops.

So why not cut out the middle man and have the rolling stock and maintenance shop be government-owned? The end result is the same, but it's cheaper for everyone involved.