Since you are running at a lower voltage, the ram actually is consuming less current.

In my test games i have crappy brand CR2032 (brand name with terrible reviews for not lasting long) going for over 1.5 years now still at 3vdc.

This is so true. I fix boards for $$$ and a cr2032 in a holder is by far the most economical way.... and it is not just a cheap solution. it works fine specially in games with 5101 rams like sys 3-7 wms, bally/stern, etc...

I have a few different cr2032 holders in different shapes. I bought some ones to fit NES and SNES cartridge games and it turns out they fit certain MPUs better.

So at 3v coin cr2032 gets 230mA..... The life would be around...

230,000 / 27 = 8518 hours or about a year.

wonder what the voltage drop over time curve looks like.. that would effect life i assume too as the current draw decreases as the voltage drops.