This is a relevant watch by James Hoffmann on how open source espresso machines kinda turned into Decent Espresso. (edit: ok, on rewatch i guess it wasn't open source, it was kickstarter, however philosophy was the similar - use off-the-shelf components and software)

https://www.youtube.com/watch?v=GKA2COJRt6M

For what it's worth, i've had a Decent DE1+ for about 2 years, and while it's very unlikely i'll change, i am excited to see what other options crop up in the coming years. for me personally, there is no competition, mainly from a quick-to-heat and pressure/flow profiling perspective, both of which are quite important to me.

my understanding is the hardware side for accurate flow-profiling really is quite hard with off-the-shelf components, so the open source espresso machine is unlikely to become a widely available commodity, unlike say 3d printers which can easily be homebrewed and work amazingly well.