> However, those walled gardens are decaying such that there might actually be demand for something better if it existed.
Some walled gardens, like facebook, are decaying. Others, like tiktok, are vibrant, still fresh and new.
Walled gardens are a natural result of the pursuit of capital. If you burn VC money, but create no moat (it turns out the walls of a walled garden are also a moat, weird huh), then as soon as you introduce a clever algorithm that introduces 50% more ads to extract profit, your users will all leave.
As such, a business is incentivized to build these walls and moats.
How do we avoid this?
Well, we do have examples. Mastodon and other open source projects eschew walled gardens in favor of free software ideals. Web3 embraces a certain "decentralized" vibe which lends itself in this direction. Universities, and other public-ish institutes like DARPA, created the original internet and many of its technologies.
Unfortunately, open source projects will struggle to advertise or find users. They do not have the initial capital to get as much momentum as the VC-funded alternatives. Web3 seems surely doomed to end up also building walled gardens for the crypto-anarcho-vibe is only skin-deep, and many a regular business is now highly involved.
This leaves government entities. The government is the one group that is both well funded enough, and has motive to create protocols which prioritize the user's freedom over profit (after all, the users will pay taxes regardless of how high the walls are).
It seems to be out of fashion these days for the government to actually do anything though, so perhaps there is no more chance of that than of a free software project managing the same.