That's only because running TCP/IP over a 1200 bits per seconds connection was close to impossible, but Fidonet had > 40 thousands nodes connect by 1990, so decentralization was already a thing back then.
When modems became fast enough to handle a TCP/IP connection it was ~1994 and by then Internet was already (relatively) cheap and available.
When modems became fast enough to handle a TCP/IP connection it was ~1994 and by then Internet was already (relatively) cheap and available.