It's true that many board vendors use out-of-date kernels and rarely update their software. But community editions like [Armbian](https://www.armbian.com) are usually kept fully up to date.

I've been using multiple ARM-based SBCs as desktop computers over a year now and have really been impressed with how software support has improved. It used to be only older versions of Firefox would run. Now most boards that use Ubuntu 18.04 (which include most versions of Armbian) will run Firefox 62.