DEXs could even be considered safer than traditional exchanges (at some points)
If you're an experienced user maybe, but for the average person it requires understanding and a lot of patience with how confirmations can either take a few minutes or even an hour in some cases.
For most people it's safe to say that the benefits of using a DEX don't outweigh the trade-offs, because there are many. It's also largely still underdeveloped because it's not profitable at all to spend time on this for developers.
What we are missing is incentive for the wealthy elite in Bitcoin land to pump money into development, but that's not going to happen considering that the elite either directly owns an exchange or has a large stake in it.
I didn't say it (because it's something repeated often in discussions) but I have to admit it's not user-friendly. But Bitcoin wasn't user-friendly the day 1 (and still not for the majority), give it time to mature. I truly believe it will be accessible to the average Joe in the near future. Don't forget the new generation is used to new technologies and it is in their daily lives, not like us who shocked to discover Emule to download free movies.
Saying it doesn't worth for the devs, yes your point is right but in the open-source world, you always have thousands of devs working for free, coding stuff used by millions of people. GNU/Linux is a perfect example. I exclude Ubuntu and Canonical, but how many forks come from Debian with devs who worked, and still work, for free? A thousand of operating systems, if not more.
You will always see some elites jumping in everything they can, Canonical and Red Hat are for Linux OS what Binance is for DEX. but that won't prevent this branch from evolving, at least it will be less anarchic.
I'm not even talking about questioning the term decentralization, because even if you use a DEX, can we really talk about decentralization if servers and other infrastructures, governance, are held by a single person or a group, or a company.
Not really...