You just described the complete opposite of the StackOverflow experience.

I disagree.

Here’s an example: my account on StackOveflow has enough reputation to answer questions on SO, but on other StackExchange sites that are very related I can’t do that just because I spent more time on StackOverflow.

The whole setup is basically repelling you from engaging by design. The site should already know from my SO reputation that I’m trustworthy enough to answer stuff on the other similar tech related stackexchange sites.

It was built for a time when you actually needed to filter out low quality questions and answers, but now that the users have abandoned the ecosystem the bouncer at the door makes a whole lot less sense.