I had the opposite experience back when I used them. Lots of flats. Don’t really know why, but it was a drag and things got better when I switched to clinchers. Anyway, I would be a little concerned about using tires that had been sitting around in a drawer for decades. I expect the rubber would deteriorate.
Well my tubular tires have a latex inner tube...which always requires pumping before riding, to return it to the extreme high pressure (~120 psi) specified. I've found that I must remember to do so. Because underinflated tubulars can give trouble.
But I used to ride them all the time. For instance, years ago, I rode RAGBRAI 480 miles across Iowa on tubulars...never had a flat. And I had a little Velox kit of needle, linen twine, patches and glue...and used to rip open deflated tubulars, patch them, and resew them! Quite satisfying.