That's OK, complaining helps the ecosystem improve. If gmail ends up being so bad that people start abandoning it (which I haven't seen yet in my friend-circle, most people are happy enough with it), it's possible to migrate to something else and still interact with people who use gmail.

Contrast that to Facebook Messenger. Either you're a user of it and can message others using it, or you're not and you can't interact with others using it. You have no choice, it's either in or out.

This is the difference between centralization and decentralization, the amount of options you have available.