There is an upper and lower limit on practical gear ratios for most folks. Very few people can "spin" a 52 X 12 combo, even on level roads. Low gear ratios could be made that would require fast spinning to move at all.... But you'd have a really big rear cog...Hehe.

An upper ratio that allows you best speed where you ride the most, and a low ratio that will get you up the hills in your area, with fine-tuned steps in between...What more could you want?

So many variables; rider strength and weight, terrain ridden in, gear carried, etc. I bought a Trek 2120 with the triple 105 setup, and find I never use the granny gear where I ride 95% of the time.
At the university where I do bike patrol, I normally never shift out of the middle ring and only use four cogs.

As for chain lube, it's pretty obvious that most problems are caused by the extremes. You see rusty, squealing chains from NO lubrication, and gooey, gunked-up messes from over-lubing.

Less may well be more except in extreme riding conditions.