There’s probably a good test for competing products that one could apply. Between my daughter, me, my mother, and my grandmother, how many of us can or will want to switch to the competing product? If it’s too hard for at least two generations, you’re probably not going to meet success because you’ve already lost a large chunk of your potential user base before we even begin discussing if the users want your service in the first place.
That's an unfair comparison though. What about someone that never used either of them ? Like someone that just hit 13 (or whatever the minimum legal age is). (See also : TikTok.)
You could also probably ask how many of those people used Twitter to begin with? In my own experience, most of my friends and family don't use Twitter at all, especially if they don't have a business or creative hobby to promote online
