ISPs would hate this and the security implications of all of these routers running various services available to the internet is quite bad.
But there's no reason why running servers should be so scary that only the powerful are able to run them. And "server" is not synonymous with "webhosting". There's a lot of p2p to be done if we want a decentralized internet.
I regularly run a Bittorrent "server" available to the internet and never had any problem. I also run a Ricochet "server" (also a p2p app), no headache either.
We have to get past the FUD and dig ourselves out of this hole.