I'll answer this as you seem to have some misconceptions.
1) The only game that sold out above 18k last season was Bournemouth. United & Liverpool both sold out at 16k. Huddersfield, Burnley & the CL game at Anfield were 17k.
2) We've agreed, or are still talking about, measures that we believe will discourage people buying away tickets just for the points. The most reliable quantitative evidence we have is from the Shakhtar game where about 300 people bought tickets & didn't go to the game. If that's typical of the average away game (and I reckon it's at least that many, probably more) then people like you will be better off as there will be more tickets going to SC holders, even after giving some to 18-25 year olds. So we believe we're tackling that side of things, like you suggested.
3) My lad is about your age and we went to away games together when he hit his teens. Had he not gone off to live in the USA in 2012, he'd probably have around the same points as you now. But getting tickets for the vast majority of games was a lot easier before 2012 and he could get them on his own card. Anyone turning 18 and getting an adult SC since 2012 that hasn't built up points as an U18 ticket holder has virtually no chance these days as demand is higher and people have accumulated even more points.
4) The club know who's buying the tickets originally and it seems there's not many younger supporters doing that so the obvious conclusion is that they're either getting them via SC's or second-hand. That takes us back to (2).
5) We'll be looking at ways in which we can "flatten out" the points system rather than have people simply accumulate points ad infinitum. That will also help you if you're a regular.
6) Both the City Matters and club representatives are firmly agreed that the most loyal supporters should still be at the top of the pecking order.