There are dozens of others, the X series, the Elite series, Even Tarr Chronicles has a Z axis.
Yes, thank you, princess, for stating the obvious.
While this is no doubt fascinating and the urge to point out the dozens of space sims that you've neglected to mention in your "only games that do this" tirade is overwhelming, I'm struggling to see any point in this.
There aren't "dozens" of space-sims. Apart from Derek Smart's horror of a game (that shouldn't be mentioned as being in the genre, unless we want everyone to laugh when we say "space-sim") - we have I-War, Tie Fighter (x-wing, alliance to some extent), Freespace 1&2 (even if those aren't exactly very deep).. and... that's it. The rest are shooters and arcade games. Because, they say, it's too difficult to play anything else. ...possibly because publishers really do browse forums like this, and think people who flaunt their stupidity as a highly valued skill are representative of gamers in general.
And yeah, devs do browse this forum and still you haven't told me what your point is. If you think for a second you're winning friends amoungst devs you're sorely mistaken. You're probably the most worthless poster I've clapped eyes on to date, and I've seen a few.