When it's cheaper to keep refilling an MRI scanner that boils off lots of helium, than buying one that loses only a little bit, then yes, you use a lot of helium.

It's not like we haven't discovered higher temperature superconductors that could be used, even if we didn't have helium.

EDIT: You can permanently fill 100 of these[1] per year with the boil off of one shitty MRI. Is uses about 1kg of He, so one year of world helium production would be enough to make one MRI machine for every 200 people. We are not constrained by helium.

[1] https://images.philips.com/is/content/PhilipsConsumer/Campai...