I know this is going to be an unpopular take, but isn't the idea of socialism that you make a unitary democratic government fill the role of Huge Monopoly Foundation so you can do stuff like fund research labs and be accountable to the public?
A socialism where the only way to work is to own a part of an enterprise (so no "exploitation"is possible) would likely work much better, and not even require a huge state. It would be rather inflexible though, or mutate back into capitalism as some workers would accumulate larger shares of enterprises.
The problem with social democracy is that it still gives capitalists a seat at the table and doesn't address the fundamental issues of empowering market radicalism. Some balance would be nice, but I don't really see that happening.
https://www.oecd.org/en/topics/policy-issues/public-finance-...
How is that 'market radicalism' ?
How is government spending ~25 trillion USD a year somehow not considered?
A good example of market radicalism at play in the US is the healthcare system. "Everyone knows" that the market is better at allocating resources, but we actually have terrible outcomes and there is no political will to change an obviously broken system. Despite having real-world examples of single-payer (and hybrid) healthcare systems out there that are more cost effective and have better outcomes.
On what market the cost of services to be rendered would be held secret, or at least obscure? Try shopping for a particular kind of surgery across hospitals. How many plans does your employer offer? Would you rather buy a plan independently? Why?
The whole "insurance" system is not insurance mostly, but a payment scheme, of a quite bizarre, complicated, and opaque kind. The regulatory forces that gave birth to it are at least as strong as any market forces remaining in the space, and likely stronger.
OTOH direct markets are a poor way to distribute goods that have a very inelastic and time-sensitive demand, like firefighting, urgent healthcare, or law enforcement. Real insurance is a better way, and a permanent force sustained by tax money usually demonstrates the best outcomes. The less urgent healthcare is, the better a market works, all the way to fitness clubs which are 100% market-based.