3x7, is actually what is on the bike I have currently reduced to. I have one in build that will be 3x9, though I prefer 3x8. I think 3x8 is the sweet spot of lots of gears (particularly if you get a touring cassette), and rugged cheap components. 3x9 starts to get fussy and expensive, and it just gets sillier from there on, but nothing wrong with rich people's problems if you want them.

On the other side, Rohloff with solid 13 gears properly spaced, is highly regarded in some circles. Even with the overlaps you don't need 33 gears to match the 13 on Rohloff using a derailleur system. But the gearheads that praise Rohloff seem equally taken with high gear numbers or derailleur bikes.

What I prefer to avoid is getting new hubs designed around high gear cassettes, and then running say an 8 on them. Just makes for an necessarily stressed wheel.

Another thing I feel strongly about for myself is if I am running a lot of gears, I need a really great shift system so that I can shift like a squirrel on crack . No point in a million gears and tube shifters, needs to be something more modern if rolling that way on the gears.

Build a balanced system, then just forget about it.