To answer to your question: yes, I'm one of "those"...I'm 31 (almost 32) and just as you do, I get my fun mostly from posing and displaying my figures. Sometimes I pick a model or two that I haven't transformed for a long time and give them the attention they crave for (in other words: I try to figure out how to transforme them since I surely have long forgotten how to :-)).
Lately, I must admitt, i've kinda started losing some intertest though. There are several reasons for that:
1)The afore-mentioned difficulty in finding the figures I want in retails (which translates into on-line purchases and addictional shipping costs...)
2)The DOTM line is really disappointing to me. I'll buy 3-4 figures, but I certainly won't bother rebuying some of them that were previously released in the rotf line (even if I'd like to have a double copy of them to display in alt-mode, such as with Sideswipe), nor will I try to complete the collection (while I've pretty much achieved completion with the previous movie lines). I mean, they look so simplistic and "unfinished"...certainly not worth 22 € for a deluxe!
3)I'm trying to resist a very strong temptation, but I don't know if I can make it... I'm talking about starting collecting Myth Cloths, from the Saint Seiya line. They're really really beautifully made, but also very expensive. So, if I'll get into that, i'll have to quit collecting transformers (I'm no billionaire unfortunately :-)). I think that for a guy grown up in the 80's Transformers and The Knights of the Zodiac are really 2 flames you don't want to have to chose between: YOU'D WANT THEM BOTH! (without mentioning Masters of the Universe :-))
Hope to hear from you soon, bey!!