You need to separate the hull value part of the cover.
Very roughly, hull value is insured at about 1-2% so a $2M plane will cost $20k to $40k per year just for that.
If you buy a $2M spaceship this comes with the territory
Also, don't expect to turn up at somebody's hangar with a $2M spaceship and expect to get it for 300 quid a month. There goes another 10-20 grand a year
After all that, if you actually want to
fly somewhere, more money....
One can pick up a well used but good TBM700 for quite a bit less than some people would think. Certainly not "millions". Especially since the TBM850 came out. But, the total ownership cost is probably 10x higher than most piston pilots pay on even on a very nice IFR tourer.