It's not failed for a lack of stores on Linux. Both Steam and GOG sell Linux games, The gaming ecosystem on Linux just doesn't compare to that on Windows. Driver support isn't there, AAA/AA game support isn't there, backwards compatibility isn't there. It is much better in recent years than ever but I think this is a knock on effect from the general resurgence of PC gaming as a whole.
Trust me, I'd love it if this weren't the case but Linux gaming has been pushed as least as long as the Linux desktop, and I don't see either getting much more traction. It's a chicken and egg problem.