I'm in the healthcare world.

SSO is a hard requirement for us.

There have been many, many times where we've considered an application where we could justify the spend at, e.g., the departmental level for the limited user base that needed it, but where SSO being bundled into higher price tiers combined with minimum user counts took a potential solution from "very easy discretionary spend" to "not happening, full stop."

I'm often the one having to make these decisions. It's absolutely exhausting having to explain to non-technical department heads that "yes, this would solve your problem at a price that fits budget, but the vendor bundles a vital security feature into a tier that inflates the price to a point that it makes this unfeasible."