Athletes are not training less at higher intensities overall. The dominant paradigm is polarized training - huge amounts of low intensity with small amounts of high intensity mixed in.
To add further, research has gone further into how intensity and low intensity improves different things - different fibres, genetics, factors of health etc. Heavy lifting affects fibers that are not affected by high-rep medium-low lifting, for example.
Huberman lab and The Drive podcast that I have listened to have had several academics in this field discuss the divergent effects of different modes of training.
> With particularly high rates of knee and ankle sprains and strains, neuromuscular training and pre-strengthening programs, which have been previously demonstrated to be effective among young athletes, may be particularly worthwhile in prospective participants
You're correct they do polarized training, but the overall times have gone done significantly. This is due to polarized training, i.e. yes when they train long and easy athletes go long and easy, however if there is high intensity training you do relatively short sessions but full on. Importantly the middle ground sessions, where people trained for hours with medium intensity have completely disappeared. Read any interview with an older professional cyclist who experienced the transition, they all mention that they are training significantly less time now.
That's interesting. Makes sense for athletes, but unfortunately seems not transferable to non-athletes, simply because hardly anyone has time for "huge amounts of low intensity" training.
Some people find success in organizing their life to get enough exercise in the natural way, as part of activities of their day, but I think the popularity of HIIT in recent days clearly indicates there's also lots of people who want to optimize for minimum of time spent on exercising. Myself I'm one of such people.
The question isn't if people have time for elite levels of training.
The real question is if you can get more done in the time available to you with HIIT or LISS cardio.
If you're sufficiently time constrained, HIIT will win.
But past a certain threshhold, LISS will always allow you to perform a greater volume of work with lower recovery costs and lower injury risks and, consequentially, greater benefits to health and fitness.
For overall health, going for "failure" in weight lifting appears to be the delusional to me; it's much better to lift at a consistent, repeatable level than to greatly increase the risk of injury chasing short term gains. When injured, your volume is going to be zero.
Huberman lab and The Drive podcast that I have listened to have had several academics in this field discuss the divergent effects of different modes of training.