Making the Highlands Climbing easier?

I decided to rent a modern bike with 7 (rear) x 3  (front) = 21 "speeds" rather than bring my 1971 Raleigh Sports fitted with a 3 speed Sturmey Archer internal gear hub. (Actually, I own and can alternatively fit the Raleigh with a wheel that has a 3 speed Shimano Nexus internal gear hub.)

In any case, back in the 1920's, this ad indicated that "3 is all you need":

To me, it's not the number of gear ratio combinations. More importantly, it's the available low / high  range. It is nice to have a finer resolution of gear ratio combinations between the low and high, but to me, that's not critical.

For example, my 2016 Trek Verve 2, also a 7 x 3 geared bicycle, has the following gear inch values across its range of combinations:

Trek Verve 2		Tire Circumference mm (measured)
Tire diameter in inches		Tire Size 37-622 700 x 35 cm
27.50	Front # Teeth	Front # Teeth	Front # Teeth
Rear # Teeth	28	38	48
34	22.65	30.74	38.82
24	32.08	43.54	55.00
22	35.00	47.50	60.00
20	38.50	52.25	66.00
18	42.78	58.06	73.33
16	48.13	65.31	82.50
14	55.00	74.64	94.29

The Raleigh with the Sturmey Archer AW 3 Speed has the following gear inch values:

Raleigh with AW Hub
Tire diameter in inches	Rear # Teeth	Front Chainweel # Teeth
26.00	22	48
Gear 1 reduction	Gear 2 Direct (1:1)	Gear 3 Increase
-25.00%		33.00%
42.55	56.73	75.45

So, the Raleigh with the Sturmey Archer AW hub has a low gear equivalent to a frequency used low gear I apply on the Trek Verve 2, and a high gear equivalent similar to a high gear I use on the Trek. I have more range on the Trek, and finer resolution between gears, but it's not that dissimilar.