The thing is: if someone is starting out now or is still early in their career they will learn and focus on react. Focusing on a technology is like making a bet and betting a career on anything that is not react right now in the frontend is a bad choice. The only legitimate alternative might be vue, but it is definitely not ember.
I would say the number of people with a career focused on ember has probably peaked a while ago.
do you see a huge influx of people wanting to learn ember and the discourse codebase?
I don’t. Its a sign that this is legacy software. That has reached the peak of its potential. There is no huge influx of people wanting to use it or work on it. Even after the increase in work from home and use of remote collaboration software. People rather use Zoom and discord.
thats what I mean by developer experience.
This is a good point. Discourse is mostly a product: a self hosted community/support forum for a slightly nerdy audience. It will never be much more than that because that is where its funding is coming from. So most decisions will be made to appease this audience.
To bring this back on topic. Replacing the markdown composer means making this software less nerdy. So it means a division from the audience it is geared towards.
It is not easy to get out of this local minimum.
so once a piece of software has found its audience a reflexive feedback loop starts that leads to more features that appease this audience, while the usability for other groups is neglected more and more.