I thought each of these were good until I tried something different. I think people moved from legacy things like Windows Live Mail, MapQuest, and Word 2000 to these services, and then never noticed the rest of the world got better outside of Google-land.

Gmail operates what is probably an industry-worst mail client. I have helped people using AOL Mail in 2020, and it is a superior experience. It performs better. FastMail is a paid service, and it's quality matches that: FastMail can run in circles around Gmail every single day.

Google Docs/Sheets is Office without all of the reasons businesses use Word. You can try to patch in some of it's holes with add-ons (I had some experience with a Mail Merge add-on for Gmail/Sheets, and it was fine, I guess, but a paid service from a third party) but with a lot of added jank. Collaborative editing was it's claim to fame, but you can do that just fine in Office 365, with a far more capable app suite.

Google Maps, Drew covered the point pretty well: Google just has the money for more data. It's prohibitively expensive to use that data yourself as a service, and others who have access to less data still manage a comparable and sometimes better product than Maps. Usually while better respecting your privacy.

Gmail sucks. They use it as a vehicle for anti-competitive "standards" and it's needlessly difficult to deliver mail to. Their new JavaScript-riddled frontends (which they seem to develop and then shrug off every couple of years) have awful performance and are terrible at doing what has ultimately a very simple task for 30 years.

Google Maps is fine. OSM is superior technically but Google Maps only wins because it has access to better data. It's not an example of great engineering, it's just okay.

Google Docs is pretty good. At least it was, the last time I used it was several years ago. I can't comment on the code, which is mainly what I'm commenting on in this thread: their engineering quality. Throw enough monkeys at a typewriter and maybe Google Docs comes out, but who knows what it looks like on the inside.

Engineering quality is about nothing other than meeting the spec- how well does google accomplish that?

It sounds like you have some issues with the design itself, maybe some issues with the business practices. Those are issues with the spec, not the engineering. The engineering team delivers the spec, they do it smoothly, they do it at scale

Highly used? So what? Might does not make right. They're definitely not cost efficient. Google's standard play is throwing tens of millions of dollars at a problem, which is not good engineering, even if it works.

Edit: you changed your comment out from under me and I fail to rouse the enthusiasm to reply to your new comment.

They are working very hard at ruining the UIs of these products though.