When was Gmail ever sold as unlimited? When it came out the big deal was that it offered 1GB, which absolutely destroyed the 5-10MB most free providers were offering at the time.
I recall a time where they were raising the limit constantly and even advertised that fact, that for most users your available space was going to increase faster than you could use it, but there was always a limit somewhere.
No, 1GB was the starting point and was considered insane at the time. Then they eventually added a counter where the storage space grew all the time. They finally capped that out—maybe that's what you're thinking of?
I recall a time where they were raising the limit constantly and even advertised that fact, that for most users your available space was going to increase faster than you could use it, but there was always a limit somewhere.