Let's simplify: FLOSS domain is the internet domain, where anyone own a desktop, a homeserver, a company machine room etc. The big tech model is the old mainframe model, or the modern web where only few own anything.
Try to mimicking them is a waste of time and can't work, pushing the society toward ownership and freedom might work, because in a way or another we will end up there being technically the sole solution.
FLOSS is the personal computer model, where you own the computer and have final say on what data is processed on your machine. If you can't try to make your software or computer lie in on your behalf, it is not FOSS.
The big tech model where trust is in the company, not the person. Business love the big tech model because it's easier to let a few credit card companies deal with the trust issue than establish a trust relationship with everyone directly (or deal with cash), because surveillance capitalism is more profitable, and because it's more profitable to rent than to sell.
The big tech model can profit first on that cost difference, and later on switching costs which would otherwise inhibit abuse.
It has essentially nothing to do with the internet, as mainframes were networked long before personal computers. Even back in the 1980s, POS terminals used dial-up to verify credit card transactions.
I mean the "mainframe model" of a single large system and many dumb terminals, now dumb terminals are named enpoints and the mainframe is someone else computer across the world.
The trust problem is easy to solve, with an open society: as long as payments got processed with open APIs and the government takes care of the frauds there is no trust problem. I do not need to trust a third party with eCash, I only need to trust my State protections.
That's still embrional but in FLOSS terms we have already more than enough, we just miss the law enforcing it and the schools teaching it to the masses.
I'm pretty sure I know where you are coming from, but I disagree with your interpretation.
The centralized trust model does not require mainframes connected-to by dumb terminals. We need only look at how Visa in its first few decades used carbon copy devices and signatures, along with eventual consistency across a network of mainframes, to gain market power.
"The trust problem is easy to solve" is laughable, as you well understand by the need for "the law enforcing it and the schools teaching it to the masses."
Well, easy to solve, means the solution is simple, not that reaching/implementing the solution is simple. Laws enforcing and school teaching are very complex, but the solution is damn simple. It's the road to it the complex part.
For health care the solution is making it totally public: all other the world the more health business exists the worst results and the higher cost you get.
There are aspects of a State to function that MUST be ONLY fully public. Again it's simple, in conceptual terms, hard to get applied in reality.
Try to mimicking them is a waste of time and can't work, pushing the society toward ownership and freedom might work, because in a way or another we will end up there being technically the sole solution.