Prefacing with - I think the spikes give an advantage.
However I think your post is a bit off the mark. One NCAA season is a very limited viewpoint, and in terms of comparing how much of an impact it has compared to the road shoes it is almost useless given the road shoes aren't really relevant to the NCAA.
Second, much of your post is a strawman argument. In all my conversations with the "the spikes don't help" crowd, I've never heard someone say "we can train harder in the road shoes so our spiked up races are faster." The one I do hear, is "the new spikes don't trash your calf muscles as much so you can train in spikes more than you otherwise would." That's a more viable counter since the spikes have only been publicly available in Nike's case since late 2020 in serious numbers. With NB, it's still virtually impossible to get a hold of the spike.
RE: the 3 different studies which have shown a 2.1% boost from spikes alone - I'd genuinely love to know which studies you're talking about. There are plenty of studies which give that kind of figure for the road shoes, but as far as I have seen there are no studies that look exclusively at the new spikes that has been published yet. You got links to these studies?
Anyway, I would still advise the "spikes give an advantage" crowd to wait until the end of the season globally so we can have some real numbers and statistical analysis of times rather than relying on one event and one season in the NCAA.