[Yeri]

Likely because 'respectable startups' (with money) can afford to buy the .com.

https://www.arbo.works/ is a new, and very respected startup. They don't have a .com (yet).

[vadfa]

Discord couldn't afford to buy discord.com, so they bought discordapp.com. They didn't think of buying discord.io or discord.app or some crap like that.