Look, if you're that uninformed, why bother commenting at all? Especially if you're in France, your takes on what constitutes socialism are weird to say the least.

SNCF operate those unprofitable routes in the middle of nowhere only because they get told and paid to do so by the state (Intercités) or the regions (TER). Private operators can bid to operate those routes too, and some do (soon Keolis, an SNCF subisdiary operated as a private company, will operate the first non-SNCF TER network).

Besides that, any operator with a license can apply to operate any route they deem profitable. And so far this has been a roaring success, with Trenitalia on Paris-Lyon (and now Marseille) and Paris-Milan being better and cheaper than SNCF. SNCF added low cost (Ouigo) trains on multiple popular routes mainly because they knew competition is coming (postponed by Covid), they probably wouldn't have bothered otherwise. This is a win-win-win for the average user.

The services that need to be maintained will be, regardless of who is the operator. Some of the profits of the private operators will pay for them (because they pay for network access, which covers the costs of the infrastructure + profit margin).