A company can throw so much manpower at the project that by adding more features and marketing the proprietary fork heavily (Extend) users start moving from the free fork to the proprietary one, and when the users are gone, the devs leave also. We end up with the original project dead(Extinguish).

What DAW are you planning to use?

Do you live in a warm country?

I think for straight 4/4 (so not felt in half time) 140 and above is definitely fast, considering the vast majority of music falls in the 110-130BPM range.