Games is one kind of software where you usually won't expect to keep your code base maintained 10 or 20 years from now. So far for the "stable platform" argument where you as a user wouldn't want anything less than open source code, unless forced to use proprietary code for external reasons.

There might be a cost/benefit analysis where some closed platform is extremely far ahead in every other aspect, but you should be very well aware of the risks of being tied to that platform.