I think some of the lock in is because MIDI (1.0, at least) just isn't good enough. I have an Ableton Push (Obviously locked to Ableton ... (mostly, there is 3rd party BitWig support)), Osmose (weird MPE+ standard), and a lot of pedals and effects which have their own, sort crappy apps for controlling them. (TC Plethora x3, Blackstar Dual Distortion, TD-3, etc.). Sys-ex is so strange to use that nobody want's to deal with it either.
The other half is because pretty much every DAW has some non-standard plugin/scripting system: Ableton with Max, Reaper with rJS, Bitwig with The Grid, etc. If I moved away from Ableton, I'd lose my M4L plugins/patches.
Standards for opening projcets cross Daws will help, I think, but the biggest 2 things that will motivate change is MIDI 1.0's slow death so that more is possible without strange, custom systems and CLAP, again for more-or-less the same reasons.