Also, you seem to forget that there are other mapping companies out there. Google Maps itself came into picture after crushing Satnav systems like Garmin, and Nokia Maps.
If Google Maps were to be dead today, again, it is inconvenience, but people would move on.
As to stepping into the most biggest services? What are they? Google search? I am sure venture capital would flow into other companies that are technically capable to provide internet search. You have Bing, DDG, etc. Sure, they are crap, but they are not end of the world. And they will improve. Google Mail? I can live without it. I can choose other providers. There are hundreds out there. Heck, I will setup my own mail server.
People do rely on many Google services, but people can also get by without any of that.
In an event of Google failing right now, it would sure be a macro-economically significant event, but for a very tiny section of the population. And they too would move on.
Until it fails, people will talk and talk and talk about big, size, impact, and other nonsense.
Just see when it fails. It's going to be a collective shrug from 99% of the population.