If its so efficient why do trash companies exist?

If private companies are so efficient then why does the government exist?

Do you see why framing the question that way doesn't help you address the actual problem? I'm guessing you don't since you seem unwilling to consider the possibility that private ownership is not the ideal solution to every service problem. I don't think you need more than a cursory glance at the state of the US to throw that idea out the window but things must seem pretty good to you if you're still stuck in that mindset.

so i can tell you from an example why private companies exist that do things that are typically done by public companies ... here in austria, there's a railway operator called WestBahn. They provide passenger trains on the route from vienna to innsbruck (roughly). That's the only route that they service. Why do they do it?

because it's one of the most provitable routes in all of austria. it has many, reliable passengers. servicing that route turns a profit. servicing many other routes, for example bus lines in some remote village, is still necessary, but obviously doesn't turn a profit as it has maybe 3 passengers at a time.

so, they pick the 1 route that's actually very profitable, only service that, and leave every other route to the state-owned alternative. that's what's happening.