0 intervention beekeeping is actually more common than you might think. Alongside those practicing it by deliberate design are many more who haven’t inspected hives for years due to personal illness, suspected allergy to beestings, fear of bees, hives in remote apiaries “lost” due to secretive beekeepers never passing on their whereabouts, feral colonies in problematic locations, hive types sold that actively preclude inspections (some types of log hives for example) and etc. Unfortunately it hasn’t in my experience led to any observable positive break throughs. For reasons I could conjecture, I seem to mainly recall the colonies I have been involved with that were left for some years being memorably defensive. Maybe that is coincidental.
Trying it in a long hive could be an interesting angle.
Sure you don’t need my thoughts and apologies if you know all this already but here are a few things to look out for. The zero inspections sounds okay but apart from watching the entrance activity you may still need to heft to ensure they have enough food. If 4 out of 5 feral / wild swarms do not survive their first winter, it can’t logically just be because beekeepers took an unsustainable harvest.
I am sure if you populate it in the first year with a split with a new mated queen, uninspected they will do great in the first year. It may be the next year the problems will start to arise.
I think the uncontrolled swarming could be the first main issue. Notwithstanding Andrew’s point about responsibility to neighbours, some strains of bees will swarm and swarm again - don’t trust the old myth they only swarm due to enforced congestion. Bees would have died out Millenia ago if the only reason they reproduced was choosing too small cavities. The issue this creates for your experiment is that the remaining bees after repeated swarming and casting may have lost nearly all their surplus honey stored to date (taken with the swarms), most of their population and be left with a virgin queen yet to start laying. Not only do they face a challenge to rebuild population to survive winter but also sufficient foragers to bring in yet another surplus to tide them over to spring. Any other bees in the area will late summer be only too aware of their frailty and alongside wasps make endless attempts to rob them out. Giving them a really small entrance in your long hive is only useful if they are still strong enough to defend it in the first place.
I suspect not treating them for varroa will have little externally observable impact of itself in the first or second year, other things such as swarming may be more significant. Uncontrolled swarming of itself will indeed help reduce the varroa burden.
Be interested to hear how you get on, keep us posted. I would rather like to be proved wrong on this one as it might free up my weekends rather usefully