How does that solve the problem that 99 % of your (potential) website visitors do not use DuckDuckGo?

Why doesn't it make sense? People rely on being in Google results for better or worse, that doesn't mean they have to like everything Google does or demands to shape those results.

"People rely on being in Google results for better or worse". Use duckduckgo if they don't like it. Google doesn't owe anybody anything. It like wanting to use Facebook resources but not wanting to use their sdk and tos. The entire conversation about AMP is pathetic. Don't like it don't use it.

Again, what does the site owner using DDG change about their visitors?

And "Google doesn't owe anybody anything." is just an incredibly lazy argument and not a good reason for why people shouldn't criticize what they do.

So the way it works... You create a site, submit it to a search engine. You do this so your site can be found. Why is this so hard for you?

No, the way it works is that if you want people to go to your site from Google, you have to spend time making a version for their own new web format which they control because of their claims that it is faster (it isn't, they preload all AMP pages as soon as you see the result in the search).