a) Much of the reason we have strong encryption is because big, bad companies like Apple have pushed so heavily for it.
b) In what way has Microsoft and Apple had their "lunch eaten" by Linux ? And on the server side it was arguably the failure of IBM, Sun, Oracle etc to recognise the shift to commoditised hardware and price accordingly that cost them market share.
A second (or third) ISP isn't going to suddenly show up at my house because it doesn't make economic sense. In the same way that two railroad lines don't get built between the same two cities.
A real scalable mesh protocol could change the economic calculation.
Like you say, these are now understood and solved problems, it is just a matter of using them and building apps that are more sticky than centralized apps. Unfortunately, us p2p-crypto people kinda suck at making "sticky" apps, so I feel like our greatest hurdle is roping design/product people in. That will be the killer challenge to get mass adoption of p2p crypto based apps, the psychology, not the technology.
Now it's up to us hackers to use decentralized algorithms and encryption to take it back. Thankfully, these are fairly understood nowadays.
And when we write this code, ensure it's got a healthy amount of copyleft built-in because multi-national software companies that live off of proprietary are afraid that this will eat their lunch the way Linux and GNU did.