Music production is hard and expensive. It requires talents to do a lot of work which can't be livestreamed and thus monetized. Can't really blame agencies or talents who decide it's not worth the effort.
Remember how Uruka was going to release an original song every 2 months in 2023? Yeah. It would have been cool if she would have been able to stick with it but I'm not too surprised it didn't work out in retrospect.