The only downside with that I've found is people and orgs tend to overestimate their future usage of X across the board, so profits rarely match expectations wi

The only downside with that I've found is people and orgs tend to overestimate their future usage of X across the board, so profits rarely match expectations with pay-as-you-go, and tier-based pricing will easily overcome you by capturing more $$ from the market. Some notable exceptions are things like file storage where people tend to underestimate what they will need I find.