Price, mostly, isn't the issue.

Living in Germany, rental apartments simply don't have AC. Even luxury apartments that are 4k+ per month typically dont. Thats changing very slowly but still a long way to go.

A lot of landlords simply don't give a shit as they're not required to install one and since there is a housing shortage, good luck convincing them of anything.

Even if you own your apartment, installing a split AC requires unanimous approval from the other apartment owners before you can install one because making any permanent modifications to the outside of the building (like drilling a hole) needs their permission.

The older generation (generalising here) often has the opinion that the cold air from ACs is unhealthy and causes cold.

Once you get past all of that, is when price can become the issue. The AC units, even top-of-the-line, cost around 1k-1.8k. Good luck finding someone to install it for you. You need an electrician and a licenced installer.

I own my house so I dont need anyone's permission. The cheapest total cost (including the 1.2k for the unit I want) is 6k. Because apparently drilling 2 holes and, running the wire and coolant pipes is 4.8k.

You can buy a portable unit for like 300e and seal the window with a piece of plexiglass with a hole in it. It's a pretty low barrier.