I'm not personally a software professional, but to me it seems that the problem is economical. Centralization and walled gardens happen because they are a way to couple the internet platforms to the economic system. I think that if done "nicely", much of the software and internet tech exist in market failure corner of the economy. It's not like there aren't many federalized/decentralized/community driven and open source projects in existence, it's just that no-one wants to fund and/or market them so that they often become non-viable in the long run.