I think that this is an important issue to consider, but also a very difficult one. The complication is that there are two factors here (1) age, and (2) experience, and neither automatically leads to better building.
In fact, I think that in general, experience (i.e. how long you have been building) is far more important than age. Age, in particular, mainly factors in when you consider how big people's collections are, since adult jobs with adult paychecks allow for much higher rates of LEGO acquisition (and I realize that part of the reason people find the Homba so cool is the smooth exterior, which requires hundreds of those arches, and all the chrome, so lots of pieces to work with CAN definitely be an advantage). Nevertheless, all those pieces are not going to be much good without some experience and skill to back it up.
One should keep in mind that the older one is, likely the less time they will have to actually build!
Experience (and thus skill level) are much harder to judge. I have only been building again (after a 20 year dark age) for a little less than two years. I know people who have been building for shorter periods who are better than me, and people who have been building for much longer who aren't.
To sum all this up - I think there definitely is an issue here regarding 35 year olds with 500,000 bricks competing with 13 year olds with maybe 20,000 bricks. But it is not clear how to solve the issue without being unfair to lots of people (i.e. the 35 year old who just started, and has 10,000 bricks, or the lucky 13 year old with 500,000 bricks - and there are some of the latter, they just have AFOL's as parents!)
Roy