TL;DR: There are many possible effects.
If Skip Bayless can make a career of poorly researched but assertively voiced opinions, I see no reason why Rojo can't. Unfortunately, I think there are a lot of factors that may or may not have contributed to the relatively fast mid-distance times this year. I've done exactly as much research as Rojo on this (i.e., none) but here are a few possibilities. I'll leave the causal determinations to smarter people.
1. MORE RUNNERS THIS YEAR. Covid means that there are far more 5th and 6th years running this year than any other year. At the bottom I've included all of the sub-3:40 men this year with their high school class and/or birthdate. I'm not making any judgments, but it would be interesting to know how this distribution compares to typical years.
2. AGE. Not only are there more runners, but assuming that runners get faster with age, we might expect more runners near the top of the regional qualifiers lists. Another effect is that even the true underclassmen now have the advantage of being in races with faster runners. I'm not sure how severe that effect is, but if you looked at high schoolers or pros you might avoid the effect entirely.
3. UNINTERRUPTED TRAINING. There has already been quite a bit of discussion about this. Yes, the sprinters had uninterrupted training too, but I'm not so sure a year of lacking consistent access to tracks for training or competition would be advantageous for them.
4. CROSS COUNTRY IN THE WINTER. Not sure if this is beneficial or not, but it seems hard to control for.
5. REGIONAL QUALIFYING RULES. Usually most athletes in the top 50 nationally can train through the regular season without worrying a whole lot about getting regional qualifying marks. It seems reasonable that the threat of only 36 athletes in each region qualifying motivated some coaches to get their athletes running fast early in the season. I would think 50th place is about the worst place to look for this reason. You really need to look at more of the distribution of times.
6. OLYMPIC TRIALS. Athletes in the top 50 might also be chasing Olympic Trials standards.
7. SPIKES IN THE 800. Are we saying that the new spikes aren't helpful here?
8. 10K RACE OPPORTUNITIES. Before the season, I predicted that the 10k regional marks wouldn't be quite as competitive this year simply because there was no Stanford Invite (at least not in the traditional sense) and Payton Jordan. I'm actually surprised the men's 10k has been so competitive this year. Either way, it's really hard to say that the spikes conclusively made everyone faster when the 10k ``effect'' is so significantly negative.
And probably many other effects that I haven't considered... Either way, I can't complain; these times have been fun to watch, and we should be excited about this generation of college runners.
3:35.96 - Nuguse, Yared ( hs: 2017)
3:35.97 - Teare, Cooper ( hs: 2016)
3:36.00 - Kipsang, Eliud ( dob: Sept, 1996)
3:36.47 - Hocker, Cole ( hs: 2019)
3:36.53 - Suliman, Waleed ( hs: 2017, dob: Sept, 1998)
3:36.97@(1) Clinger, Casey ( hs: 2017)
3:37.17 - Garcia Romo, Mario (dob: June, 1999)
3:37.21@(1) Bons, Lucas ( hs: 2018)
3:37.55 - Franco, Talem ( hs: 2013)
3:37.66 - Adams, Ryan ( hs: 2015, dob: July, 1996)
3:37.73 - Ryan, Paul ( hs: 2015, dob: May, 1997)
3:37.76 - Comber, Casey ( hs: 2015, dob: Nov, 1996)
3:37.96 - Mantz, Conner ( hs: 2015)
3:38.07 - Knevelbaard, Kasey ( hs: 2015, dob: Sept, 1996)
3:38.09 - Herrera, Eduardo ( hs: 2016, dob: Sept, 1997)
3:38.17 - Hunter, Charlie (dob: July, 1996)
3:38.29 - Brandt, Robert ( hs: 2015)
3:38.52 - Kioko, Athanas (dob: June, 1995)
3:38.58 - Tanner, Sam (dob: Aug, 2000)
3:38.60 - Dolan, Sean ( hs: 2018)
3:38.72(1) Salisbury, Jack ( hs: 2016)
3:38.79 - Fogg, Adam (dob: Jan, 1999)
3:38.87 - Hamlin, Jesse ( hs: 2019)
3:39.02 - Grijalva, Luis ( hs: 2016)
3:39.03 - Zarate, Diego ( hs: 2015, dob: Sept, 1997)
3:39.17 - Anstey, Jack ( hs: 2016, dob: Apr, 1997)
3:39.27 - Ratcliffe, Thomas ( hs: 2016)
3:39.43@(1) Troutner, Aidan ( hs: 2018)
3:39.44 - Stallings, Zach ( hs: 2017, dob: Aug, 1998)
3:39.49 - Stanovsek, Mick ( hs: 2015)
3:39.73 - Tubby, Brandon ( hs: 2016)
3:39.79@(1) Osterstock, Nate ( hs: 2017)
3:39.85 - Davis, Jonathan ( hs: 2016, dob: Oct, 1997)
3:39.87 - Facioni, Zach ( dob: Apr, 1999)
3:39.91 - Bedard, Simon ( dob: Jan, 1997)
3:39.93 - Lagat, Festus (dob: Oct, 1996)