The ignorance and hate of ultrarunning by most LRCers is astonishing, even considering the overall level of hate and ignorance here in general. At one time it may have been true that the level of competition near the top was substandard, but that's no longer the case. Starting about 10 years ago, the ante started getting upped considerably, and it keeps increasing, particularly just in the last few years.
One thing that has changed is that more formerly elite or near-elite tracksters have migrated into ultrarunning. Only a portion of them succeed, however. Most do not, for various reasons.
A couple of good examples who have are Jim Walmsley and Hayden Hawks. On the other hand, Sage Canaday is a near-elite marathoner, and one who has had some hits but many more misses on the ultra circuit. Sage offers an experienced perspective of someone coming from an elite-type background and patiently answers questions here on LRC from time to time about why elites often find it hard making the transition.
If you have followed Walmsley and Hayden in particular on Strava and take a look at their HR output and so forth, they are training monsters. (You can't go by pace much during their peak training blocks, because they put in 20,000 to 30,000 ft or more of vert training in a week at those times.) Both are clocking up to 130 or 140 miles per week of very hard altitude training during the peak weeks of their target training blocks. Walmsley at 7,000 feet in the Flagstaff area as his home base, and last year 9,000 feet in the Silverton, CO leading up to UTMB. Hayden typically training at a little lower elevation around 5,000 to 6,000 feet in Utah.
But even these guys can find themselves getting beaten in bigger races by ultra runners who have never been track elites, when they make missteps in their race or training strategy, or due to lack of experience.