Let me convince you otherwise:

1. Who set that expectation in the first place? Don't all cut-throat corps undercut the previous established companies and gained a lot of market share by being "loss leaders"?
2. Do you think YouTube would dare to go completely Pay only?
3. Lack of competition is not an excuse to double dip on both customer data and advertisements.
4. People who say that we need to pay for server costs should consider that streaming services are now asking for money but also introducing adverts. The money is too lucrative for them to leave on the table.
5. Everybody is happy to pay when there's 1 service or 2 services that give them everything for a nominal fee. Cases in point: Netflix, Steam.
6. A lot of people pay for twitch because it's the only platform they care about. Paying for A platform doesn't mean we will pay for ALL platforms.