For as long as I can remember, I have begun my scales with C major. When I practice Sevcik, I typically begin in C and add sharps and flats. I have a feeling that lots of people have been doing this for a long time.
The word Gamut, as defined by Merriam-Webster, comes from the Greek letter Gamma plus Ut, and seems to be the span between G and C. Perhaps if Merriam and Webster were musicians they would have considered other possibilities.
Their etymology doesn't make sense to me, considering the French word for scale is Gamme, and the use of "Ut" as the tonic pitch of a scale goes back at least to Guido D'Arezzo (11th century).
The three-language scale books I used to enjoy reading while I played through my scales during my teenage years prompted me to think that the obvious meaning of "Gamut" was a scale that went from Ut to Ut, whatever that "Ut" might be, since "Ut" is the tonic pitch in a "movable Do" system. When the fixed "Do" came about (sometime before the days of Machaut), "Do" became equal to "Ut."
Why am I thinking about this? Because I decided today to break the cycle (or circle) and begin my journey through the tonal musical spectrum with G, adding sharps, and then subtracting flats. In other words, I played my scales backwards. The beauty of this is that if you go up and down you don't have to read the music backwards (though you certainly can).
What can be gained from this? It forces me to pay more attention to intonation, and it adds variety to my days.