And even Microsoft doesn't "dominate" my digital life. I think it's about the choices you make. You're choosing to be dominated. Maybe you get some benefits using those companies (Prime looks good sometimes), but you don't have to be involved with any of them.
That's not domination.
However, we are not really representative of most people. One has to actively search for OS-es other than Windows or OSX, one has to actively for email providers other than Google or MS, and it's downright impossible to get a smartphone without any of them. The large majority of computer and internet users just (correctly) choose the most popular option.
The second thing is that you can often choose one of those five, but it's much harder to go without any of them. When you use Bing instead of Google, or AWS insteaf od Azure, or Android instead of iPhone, you're not really escaping their stranglehold. You're just shifting the balance of power between those five.
So still, it just doesn't seem like "domination" to me. Yeah, so some of the services I use use AWS. They probably could choose one of a bucket load of web service services out there. Sure seems like there is a lot of choice in that market.
MS is still huge, and possibly on the decline for the average consumer, but government, and many business are very reliant and spend a lot of money as well as time on products and training.
It's not a conscious decision (well, except for the searching part - I like the no tracking on DDG) - Google just doesn't offer things I need.