Minimum mileage needed for 2:55 marathon

You're there for 2:55. Maybe the race you hit the wall was a fueling/pacing issue or it wasn't the best weather day. Generally 50-60 range is what people are running for 2:50s. That's to run close to potential -- obvious someone with more speed can hop into a marathon & run 20min slower than what their 5k says they can & still run a time like this.

Sub-2:50 is on the table with your 10k/half. I don't think you're running junk miles at 60mpw.

I did it several times off just under 40mpw. I would have the occasional 50 mile week and then a 32 mile week. 4 days a week, 2 hard efforts and 2 medium efforts. My 10K is nearly identical to yours and half PR is slightly faster, but I question that course as it was a small local race and 3 min PR for me.

You should be able to do it based on your shorter races with the right pacing. Ideally, you want to run at least 50mpw, but in my case life with a busy job and family always seem to take priority.

26.2 miles to be exact.

I did 2h52'54 in Valencia, 10 weeks averaging 50 mpw + 2 weeks easier.
I ran a half in 1h20'54 6 weeks before the race (all out).

The minimum is zero. I ran 2:52 on 35 MPW and I am no world class runner.

Silly man. People on this board don't need to train to run a 2:55 marathon. If you're doing more than a few easy jogs a week then you're trying too hard.