I'm not sure it is the win you're suggesting. I had brief stints with CVS and TBH it really sucked.
Luckily when I started coding seriously (which coincided with my first job), SVN just reached 1.0 and it was OK. This was 2004 already.
IMHO, the whole situation was fixed only after Linus decided he had enough of the crap and wrote his own.
All I wanted to stress is that the "lock-before-you-can-touch" approach was the norm in the enterprise world at the time. IMHO, this fact alone made SVN (even CVS) better than all the commercial products which I used at the time.
When some of the "enterprise" world started adopting SVN and commercial products started relaxing the locking mandate, the open-source world was already embarked on the decentralized model (git, darcs, arch, mercurial, etc).
But, yeah, ClearCase sucked pretty hard and was frustratingly slow. Also, too easy to miss adding files to source control and really annoying interface to _find_ view-private files. 0/10, would not use again unless I had a gun to my head.
Now it's different, we think our new tools are good, and we really mean it. But it's different.
What had you used that was better? CVS seemed like quite a step forward compared to RCS and the other available options.
Especially when compared with the options we have now, I think it's slightly misleading to say OSS solutions were in any real way better back then...