go fetch me the solid coupla weeks of hot weather sprint training he's done in oregon in december/january
then fetch me last indoor track wr that was faster than outdoors
First, who says he's stayed in Oregon the whole time? I have no idea if he's traveled to train or not but it's certainly possible.
Second, you can easily duplicate heat training by over dressing during a workout in 50 degree temps.
Third, it's easily possible to reach maximum fitness without "hot weather sprint training."
Fourth, the fact that outdoor WRs are consistently superior to indoor is a function of the calendar, not the venue. Yes, tighter turns are a bit slower, but the surfaces are/can be just as fast. Further, there is zero wind/sun and you can control for perfect temps. Outdoor times are superior because that's the main season that everyone peaks for. Countless guys either skip indoor entirely or simply train through it without even attempting to peak. Basically, indoor is to outdoor as conference is to nationals in terms of the level of competition. Not only does that reduce the pool of people prepared to run fast, it also reduces the level of competition for people who are prepared to run fast.
Fifth, the fact that most guys' outdoor PRs at 5,000 meters might generally be 10-20 seconds faster than indoors means nothing in terms a particular athlete on a particular day. Completely possible for a guy in peak condition to run a time indoors that is equal or even superior to what he would do outdoors in the same shape. Some guys even have all-time indoor PRs faster than outdoors (see Coghlan, for example).