"Tim Berners-Lee wanted a decentralised web but he designed a centralised web. The centralised aspect of the web is inherent in its client/server architecture where many clients connect to a relatively small number of servers"

At the time when TBL was creating the web in the early 1990s what were called "fat clients" were still quite new. Before then it was mostly just dumb terminals connected to a single computer. Servers powerful enough to host platforms the size of Facebook didn't exist until the 2000s.

So the hardware limitations did to some extent constrain the type of architecture which as possible during that decade there was a growing but mostly decentralized web, with some exceptions like Compuserve.