Is Text-based Online Web RPG still a thing?

I'm thinking in create a game with a mechanic like the title says but i don't know if this is a thing to generate some passive earnings. I mean, i don't want this to be my full time job, but $100 for example would be an excellent passive income.

What you think? I already have the skills to do it, i'm full stack developer with 3+ years of experience with php, nodejs, mysql/mongo and vue.