[Jim Zondag]

Ask the question: "Why do we restrict access to the Robots".
The answer is not because to restrict burnout or any other reason stated here. This is a side effect and not the original intent.
The real answer today is "because we always have". This is not a very good reason. Almost no one who works at FIRST other than Dean and Woodie were here when the decision to institute this policy was made. It persists as an artifact of the past and little more. It really makes very little sense in the modern context of FRC as a season long sport and not a single event.
Look around at any other machine sport on earth and you will very rarely find any kind of restriction like this, if ever. I know of nothing else like it. If your build machines, you need time to learn to use them, time to fix them, Time to test them, and time to improve them. Contintuous improvement and iterative development are two of the core aspects of good engineering process. FRC deliberately squashes these effort for reasons I have never understood.

If you told a race car team that they could not have access to their car for weeks before the big race, they would laugh in your face. Most other machine sports are just as intense as FRC, some are more so, but none of them attempt at putting any extra artificial constraints on access to the machines. When race day comes, you go to the track; that is your only time constraint. FRC does not need to be different.

I actually find in practice that the machine access rules make the sport of FRC much harder for the weaker teams, and give a huge advantage to the well resourced teams. These rules are a major driver of cost, effort, and time investment. they makes the void between the 'haves' and 'have-nots' wider than it would be if we have free access to the robots.
This is not just opnion: the performance data from many seasons of FRC history support the statement that "Teams get better when they use their robots" (Duh!). The way it is today, the well resourced teams have many, many times more time with their robots than everyone else. My team will effectively spend several YEARS of FRC match time driving our practice robot every week during the competition season. We will never have a world in which most teams can build multiple machines per year. The only solution which approaches a more equitable solution is to remove the access restrictions for everyone. As long as this disparity exists, there will be a large amount of stratification in the league.

As for mentor burnout: I personally would spend less time, have lower stress, be able to better empower my students, spend less money, and have more fun if there were no machine access restrictions. The "myth of the 6 weeks" is simply not true, and it has never been true in my experience. Being successful in FRC takes longer than this. We should all stop lying to ourselves.