How true! I took two days of lessons with Buddy Emmons in Nashville in 1981. At one point Buddy played a S-10 through a little Peavey Bandit amp... and "that sound" was there! Big, rich tone through a little Bandit amp.I'm more and more beginning to think that tone primarily is in your hands.
IMHO much of a player's tone is in the hands, the vibrato, the picking, the right hand attack, etc. The amp settings are important too... and the speaker configuration, the wattage, tube or solid state, etc.
Having said that, I have noticed a big difference in tone between lap steels. For example, between a pre-war Gibson lap steel and a Fender Stringmaster. Or between a National string-over pickup lap steel and a National string-through pickup lap steel. There Are differences in tone in the instruments. Some are "darker" in tone, some are "brighter", but a great player will sound great on any adequate instrument.
I'm reminded of the time I heard two guitarists on stage swap equipment. Each played the others guitar, amp, effects, etc. Each player tweaked a few knobs, and within a few minutes each player had his own sound back!