In weak or even average track states sure, but in the stronger states (CA, TX, IL, OH, FL) the guys running 23.5/51.5 often have a greater potential to score if they move up versus if they try and race the sprints. Also keep in mind that states where a 51.xx is scoring at the state level are the states where 1:55 (or hell, 1:57) is often good enough to win.
Even pretty good high school 800 runners (let's say sub 2:00 and faster) have significantly fewer miles logged, years training, etc. than collegiate and adult runners. There's nothing mythical about aerobic development; there's a reason why you'll see high school boys every year running 52/2:00/4:45 alongside XC times north of 17 or 18 minutes. Bringing up Symmonds hurts your case; the guy improved from a 1:48 to a 1:42 over the course of his career by further developing the aerobic side (1500 from 3:45 --> 3:34 while his 400 barely budged).
Definitely true in the collegiate and adult ranks, but very few at a high school level. For reference, I went through the 20 athletes who ran 1:54.92 - 1:55.0 this past outdoor season). 16 of them had recorded 400 times. All 16 of them had run sub 53. You can probably extend it to the 30 athletes closest to 1:55 and get a pretty similar distribution.
Again, there are certainly athletes out there who can go 1:55 without running sub 53--you see them all the time at the collegiate level. But a high schooler running 1:55 without sub-53 speed is extremely rare, and those are often the kids you see putting up monstrous performances in the 32 and 5k, placing extremely well at national XC meets, and often going on to perform well in the 5k and 10k in college.