That amount of thermal insulation is pointless overkill if you don't control air infiltration. Assuming you can seal a house as airtight as a Thermos bottle, then health issues arise from the lack of fresh air and the increased concentration of trapped toxins such as biological expirations, bacteria, virues, materials outgassing, etc. The complexity and cost of a sealed air-filtered bioenvironment is beyond the reach of most people.
Did you know that the UBC only requires openable windows in assisted living homes? That means your mother/grandmother living in one, with dementia, probably in a wheelchair or using a walker, has to get up every hour or so and open/close their window so that they can get breathable outside air. In a nursing home or hospital you get 10 air changes/hr with mechanical ventilation, in assisted living you get NONE.
As to caulked-tight/no infiltration living units, a heat exchanger is as simple as a small fan and double pipe duct : outgoing exhaust air heats incoming fresh air. Yes, you lose about half the heat but it isn’t that big a deal energy-wise. The code requires 2 air changes/hr, look at the numbers, not that much vs OXYGEN to stay alive.