Yes.
Why? I think it has a lot to do with perceived power.
Wizard sounds okay. Wizard/Master Specialist/Thaumaturge/Malconvoker to the uninitiated sounds like a physical god. Of course he's really not, and in fact is far from it, and it would probably be much simpler to say, "He's a summoning focused magic user", but that's not nearly as impressive.
I would also guess that it helps make my character seem more like a beautiful unique snowflake. There are plenty of wizards, probably a more than a few master specialists, likely a couple of thaumaturgists, but probably only a handful of malconvokers. The more names I can add to my list the more unique and impressive I sound. It likely stems from the whole "I am my class" mentality take to the logical extreme. I compare it to the people who work for a living and desire an unnecessarily long title to describe their job, such as "Executive V.P. of Personnel for Overseas Inter-Corporate Relations." People like to claim Secretary was changed to Executive Assistant for sexism issues, but ask yourself which one sounds more impressive?
Even people who stick to one class I would wager still draw on no fewer than three sources for actually compiling the character. After a certain campaign, one of the most dangerous thins I can say to my gaming group now when we talk about things we would like to play is "Artificer 20". But even with that single class I still probably wind up using ESC, Magic of Eberron, Explorer's Handbook, and the Stronghold Builder's Guide for feat selections... and nearly every single book in the D&D multi-verse when picking equipment.
I also don't see anything inherently wrong with it. It's only a problem when you are trying something new and look at your Archivist/Sacred Exorcist and feel it's not ready to play for no reason other than it doesn't have enough names in the title.