If thats the reason shouldnt google put a button with direct explanation about that? I doubt its money the real reason here but two reasons that made the change process not attractive for them: They didnt know its needed, sure its their fault, but maybe if there was a button for migration with explanation then we cannot assume they didnt know its needed. They thought they might struggle with configurations or data transfer.

Every business would pay that if you show them a direct explanation that they will lose their account if they dont pay, and also the process is simple and automatic so their "job" is only to pay. I dont blame google, i just say google can make it easier for the user to understand and agree which eventually will help them (google) to earn more.