Oh, don't totally disagree -- my "hypothesis" though on www.newmutants98.com though, is unlike ASM 128 and Hulk 181, that NM 98 had a ton of copies well preserved in bags and boards from the very start, versus comics from the '70s which were still considered disposable kids entertainment at the time...
...so, not saying that ASM 128 or Hulk 181 will ever depreciate. Because even though they had high print runs, they had a low relative rate of being well preserved. NM 98 on the other hand...
VF / NM