The problem is that these apps come with a built-in doomsday. If they ever get popular enough to be meaningfully on the radar of the company whose app they're replacing, they'll be attacked both legally ("you're violating our TOS by using this app") and technically (removing API access or obfuscating internal APIs / pages to prevent scraping).
Efforts like youtube-dl are a constant arms race between google making changes that prevent it working, and the youtube-dl devs pushing fixes. It's a piece of software where "too old to be useful" is measured in months as tons of things don't work anymore.
These companies will never willingly give up control over the user experience (especially if they NEED that control in order to serve ads), and they'll use every method at their disposal in order to do so. Discord already threatens to ban anyone who tries to use a third party client - how long until twitter does the same?
I think these hypothetical apps should be based on html embeds. The big tech companies are not going to remove the ability to do web embeds of their posts/videos/tweets, because embeds are good for bringing traffic in.
With those services that don't have RSS (Youtube does), you will still need a little scraping just to discover the URL of new tweets/posts in a given channel. But it would be just basic scraping and probably more manageable compared to something like youtube-dl.
Efforts like youtube-dl are a constant arms race between google making changes that prevent it working, and the youtube-dl devs pushing fixes. It's a piece of software where "too old to be useful" is measured in months as tons of things don't work anymore.
These companies will never willingly give up control over the user experience (especially if they NEED that control in order to serve ads), and they'll use every method at their disposal in order to do so. Discord already threatens to ban anyone who tries to use a third party client - how long until twitter does the same?