Wrong. Gates and Allen used Harvard's University mainframe to do their first gig, then paid for other mainframe time:
All the students wich are entitled to access to the mainframe worked typically on a single mainframe which was also used for the university accounting etc.
Mainframes were, using the more modern words, the big servers with the capital S, effectively.
Hobbyist keyboard alone (without the TV) had the price of nearly 1000 US dollars equivalent today in 1975
The cheapest self containing computer that year had a minimal cost of 30,000 of today's US dollars.
The "operating system" of it were Basic and APL, and it had the storage of 200 KB.
Now compare all this to the "server" which started this discussion. The claim was that when Gates started he didn't need "servers."
But were they selling Altair_BASIC running on said mainframe? No they were not, hence they did not have servers. They used a mainframe as a dev box.
You can't redefine my terminology just to suit your own viewpoint.