That’s a fun math. I just checked mine: 96000 minutes. 2 minutes per song is way too generous as an assumption, for me everything seems to be > 3 minutes so ~20000 streams.

I’m paying for a family account (that’s around 250/year) and there are 5 people on it so my usage is 1/5th of that (50/year)

So that’s 0.0025€ per stream. I don’t think your assumption is unreasonable.