There were definitely racks of modems at small scale ISPs in the 90's. Once line speeds hit 56k and required more sophisticated equipment at the exchange/ISP,

There were definitely racks of modems at small scale ISPs in the 90's. Once line speeds hit 56k and required more sophisticated equipment at the exchange/ISP, a lot of small ISPs got squeezed out because of the investment required, and sold their phone number and customer base. A lot of consolidation started happening at that point, from what I remember.