Someone mentioned it above that this happens in all RPGs. Rogues rarely get excited about finding a room full of spellbooks like the Sorcerers and, maybe, Clerics do. For the most part, a fighter isn't going to be much use disabling a trap - unless he's just full up on health points and figures the best way to disable it is to trip it (been there done that).
The trick is to have as much general use activities spread in among the specialties. If you have one person who is the pilot, then push others into a turret with Gunnery, doing repairs with Mechanics as 2P51 just said. Games like this actually accentuate this issue on purpose to make you want to be a part of the team. There are [a lot of] games where I am not able to get everyone gets something geared to their specialty but I try to not go more than two sessions without covering everyone. That said, I had one adventure that spanned several weeks that was designed specifically to require a lot of sneaking and skullduggery. There were a lot of old Star Trek misquotes those sessions "**** it Jim, I'm a pilot, not a Bothan Spy"
Edited by Varlie