Yes, you have to choose your dependencies carefully, but where does it end? Steam could go away tomorrow. The game engine you license could go out of business. Your hosting provider, your DNS provider could kick you off.
If you don’t entertain new platforms, you are leaving money on the table. I’d wager that Japanese game manufacturers missed hundreds of millions of dollars by being late to embrace Steam.
Sell your game on your own website too.
> The game engine you license could go out of business.
Use a FOSS engine, so even if the original maintainers totally abandon it, someone else can fork it.
> Your hosting provider, your DNS provider could kick you off.
You can switch to a new hosting/DNS provider transparently to your customers.