The moment that agreement becomes invalid is the moment a person has the right to become frustrated.
There are terms for something that works 99 days but on the 100th day makes you feel like gotterdammerung.
They are a crappy service, fails QA 101, never trust google and i'm switching my email to something else
You're certainly within your rights to feel that way, and if you do, I certainly encourage you to migrate to something else. If that's really how you feel though, I'm guessing you already would have unless... just maybe, the service is better than you admit.
The risk means that even if Google provides the service free, it still can have a cost for the user that can be very high depending on the importance of the emails the user is locked out of.
It also means that the cost is invisible 99% of the time, which is why people keep using Google services. After all, most companies that offer network services mitigate the risk for the user by allowing the user to contact them for help if things go wrong.
For example, Amazon Web Services and Microsoft both allow you to purchase support. However, Google seem to only provide support when they decide to invite you to it.
In my personal case, my main email of 16 years is becoming increasingly spammed. I needed to find another email to migrate to, and decided to try out Gmail. Gmail has failed my evaluation.
Google (read their terms) reserves the right to mine your communications for information that they then sell to advertisers. You're doing THEM at least as much a service.