some good points here but to call it a mess and unenjoyable is such a stretch. If anything, it's more competitive and kids are running faster across the board with deeper talent than ever before. You can chalk some of that up to better training and technology, but it's legal and it's still fun to see.
I'll tackle your points in my opinion though.
- some highschoolers run races with collegiate and even pro guys but imo this is fine. we rarely see kids forego their highschool eligibility to race pros (I'm admittedly a little murky on how the rules here work) but i like the idea of giving kids the best opportunities. There is an argument to be made for continuity, with how in the past rules were more stringent and kids had less opportunities.
- multiple national champs I fully agree with. it is stupid. the meets should coalesce. I don't hate that nb is on the east Coast, and Nike on the West, but many kids from the east side of the country travel to nb and vice versa, and I'm overall in favor of creating one definitive national championship. Would also concentrate all the talent, make it even more exciting. Adidas is quite clearly inferior to the other two in my view. New balance seems to have the premier indoor meet, so maybe let nike have outdoors? I don't really care who sponsors it, but have just one.
- what abundance lol. the only one I know of is kitchen this year. sure there's a few others. 18 vs 19 is not a huge difference, in highschool when kids are going through puberty at different speeds anyway. Some kids start real early and some get a big boost later on. but by 18 and 19 this difference is minimal. not the same as 14 or 15 where some boys have not started puberty and other kids are rather far along.
- 9 seconds over a mile is a hilariously bad estimate for super spikes. world Athletics has found them legal. Technology will always advance and push the edge, sure it is a little unfortunate we won't have a perfectly even playing field with the past but that is how this sport has always been, the past 100 years there have been lots of developments, not just super spikes, which are worth MAYBE .8 a lap over an absolute best case scenario. But almost definetely less.