Network effects
They sound fancy and complex but this is a good explanation from XKCD. What I really like about it is that it emphasises how competition among networks is not unambiguously beneficial to consumers. For more on network effects and why they’re not the same as externalities check out the Palgrave description.
Competing *compatible* networks, that’s whatcha need.
Is there any incentive for successful networks to lower the barriers to exit?