The following are the statistics from BRDAD's cache hider statistics:
Regular - 1359
Micro - 1259
Small - 846
Not Chosen - 141
Other - 109
Large - 22
While there are a lot of micro caches out there, they are still outnumbered by traditional sized caches. Many new geocachers start by placing micros. They are plain and simply easier to place. Many of these new cachers evolve and start changing the way place caches. For many it just takes a bit of time.
So, while there are micros just about everywhere there are certainly plenty of other sized caches out there as well.
I'd really rather not cache, but I am helpless in the grip of my compulsion!