Spray foam pays for itself, so it's basically free in the long run. Interesting enough people don't bat an eye when someone quotes them 20-30 k for a new Kitchen but if you quote someone 20-30 k to insulate their entire house they look at you like you killed their mother and sister.

The average home has 2000 ft of linear cracks. Everything from poorly sealed doors, windows, and envelope. It's like the equivalent of keeping your front and back door open all year around. So even after spray foaming there is some leakage (blown door test).

Really, Spray foam isn't that expensive, you should be paying about $3 -$4 a sq/ft at around a R-21 which is cheaper than most tile or carpet installations.

https://huntsmanbuildingsolutions.com/en-US/

If I were building a house I would probably go with ICF forms all the way up and Spray Foam the attic and basement floor (under the concrete floor). If I were renovating, I would Spray Foam and try to make the job large enough to cover the contractors minimum charge. Even a couple of rooms can really help the utility bills.