New gas pipeline in Berlin costs €5000

Gas will still be in the ground for thousands of years and can be burned relatively cleanly. Pretending now that the train has left the station and electricity (which also somehow has to be generated) is the be-all and end-all is, in my opinion, nonsense. I do not believe that the electricity price will significantly decouple from the price increases of other energy sources. Self-generation is all well and good, but naturally can only cover a manageable part of the demand. In older buildings, gas still makes much more economic sense than an air-water heat pump.

Gas will still be available in the ground for thousands of years

Source please... I read something between 40 and 67 years

Source please...
I read something between 40 and 67 years

Well, it was possibly a bit optimistic and a shot in the dark.
Apparently, there aren't really usable numbers to be found because there are constantly new developments.
Your numbers come from the currently developed sources.
Other sources (which I naturally cannot link) estimate the supply from 'unconventional sources' to have a range of over 700 years...
The truth will lie somewhere in between.
Currently, from an economic point of view, when choosing a heating system, you definitely don’t have to worry about the availability of gas during the lifespan of the heating system.