That’s not the case, and it needn’t be the case. In common law jurisdictions courts rarely order specific performance. So for perpetual contracts, which do exist, a party would just need to pay expectation damages to the other party to end the contract.
On the consumer side perpetual contracts are unfair, and subscription consumer contracts essentially always include termination clauses on both sides.
In the end this usually means having to give reasonable notice, which can also be an implied term.
Now, if you consider commercial contracts in general that's different.
> All subscription contracts provide that they can be cancelled by either parties with reasonable notice
Apparently no notice was given. Either way, this seems to me like it's a bug rather than a contract issue
In this case it seems that Google's promise was only never to raise the price.
That might sound misleading because consumers are not used to have a company cancel on them (they want to get paid, right?) but that's always a contractual possibility.