The whole point of federation and open protocols is that you aren’t tied to any specific piece of software, or any single provider, or any single set of features. People can experiment and innovate and collaborate and expand to build new things on top without losing access or interfering with people who prefer the old methods. People or software that abuses the system on the other hand, can be blocked or defederated.

A healthy software ecosystem should have many different pieces of software all written by different people with different goals, but all implementing most of the same things. Some will be more popular than others, and the popular ones might not agree with your own personal tastes, but that’s just life. The point is that we (and software developers) all have the freedom to choose how we interact with this system without any formal rules or maintainer group deciding what is allowed and what isn’t (except within their own software and/or instance).

and they will be cross compatible enough that it won’t be much of a deal what project is running underneath?

They are already cross-compatible enough, they are as cross-compatible as they need to be. It’s not clear what more you could ask for. If you want them to all look and work exactly the same then what’s the point of having different software at all? You’re acting like the different features and choices are a downside when it is in fact a benefit. Pick the one you like the most and use it. If you like Piefed’s hashtags, then use Piefed, it’s great! There’s nothing “locked away” in Piefed, everything in it is available to everybody, as it should be!