TCP/IP centralizes. Why am I stuck with one ISP? Scalable Mesh is the solution. I just GPL'd my project I'm working to build: https://GitHub.com/IsoGrid/IsoSwitch
No. TCP/IP can work just fine over multiple ISPs, Google "asymmetric routing". Also, look into cloud load balancers like cloudflare, then realize you can use A records to load balance over more than one of those with multiple different backends. The problem is physical diversity of connection at any one location, not some perceived weakness in TCP/IP.
I assert that TCP/IP is actually the cause of "[lack of] physical diversity of connection in any one location".
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.
That are two things that really killed the peer-to-peer nature of the Internet---NAT and firewalls. Both work to make a true peer-to-peer connection difficult.