You most definitely can convey meaningful messages in a limited amount of time, and that's exactly the point, enforcing conciseness you end up with higher information density.
Decentralization provides the additional value of resistance to censorship and algorithmic biases.
Now, because these opinions/statements are not debated due to the fact that not everyone is willing to pay Elon for a set of blue pixels and the ability to post longer form content, they stay there, fueling the echo chambers of opinions that the authors' audience holds, never to be questioned again.
I exaggerate a bit, but I hardly believe I'm the only one who thinks "fuck this, I don't have time to spread my message to multiple tweets/restructure it to fit the character limitation/etc".
Probably also depends how comfortable you are sharing deep or personal thoughts with others. Also how much you are interested in reading about a particular person's thoughts. In my case I don't know enough people that care about the things I'm enthusiastic about so I've built up a habit of being direct and to the point.
Having said that, the idea of social networks like twitter, is to spark a discussion, otherwise you would write a blog. Discussing ideas in twitter is very painful with its limited number of characters.
Unless, of course, all you want is a 2-3 sentence “revelations”, in a form of motivational posters we used to see around 2010, which you accept without questions. But then, is twitter really that different than 9gag for example?