> This is a pretty common point of view, but I wonder, how would this be enforced in a free-and-open software development ecosystem?
It wouldn't be enforced. The beauty of OSS is that there is no enforcing of solutions. Even when you touch something as core as the init system or the graphics system, the solution must prevail by technical merits. There is marketing, but thankfully this is a world of technical evaluation first, selling second and never one of enforcement.
Change is more difficult, but so are mandated blunders.
Seeing how well most developers welcome change in their favorite OSes, editors, etc, I imagine a world where every developer bends their efforts towards the one true chosen solution, and are not allowed or able to choose to "waste" their efforts on another solution wouldn't yield as vibrant a software ecosystem as we have now.