That's a good question, but it is different. The equivalent would be "if everyone just agrees that a bitcoin is worth nothing, then it is worth nothing".

I don't know if I have a good comparison here, but maybe something like "if the bank keeps your money for a little longer before validating your transaction, they can use your money for a little longer and make more money from it". Of course if your bank says that a transaction takes 1 year, you will go to another bank. But if they say it takes a day...