This may sound true, until you realize that matrix is just as extensible, and it has the same problem with clients which don’t support the full set of features.
This is not the problem. I’d say that XMPP is just as alive as Matrix, except it’s not so hip anymore. It definitely feels faster with more mature clients.
Pretty sure the client feature parity problem is inherent to open ecosystems with many vendors with varying priorities and budgets. Just look at the web back when there were more browsers in the game, or email clients etc.
This is not the problem. I’d say that XMPP is just as alive as Matrix, except it’s not so hip anymore. It definitely feels faster with more mature clients.