It's strange really, so many will accept a method of doing something whether it gets decent results, or not and kid themselves, that their chosen method, or product, is the only way.
Twenty years ago, gum was sprayed with an aerosol product which made it hard and brittle, but it pulled out a lot of fibre when scraped. Never worked then, doesn't work now.
More recently loads of solvents came on the market, some better than others and used with caution, they worked / work very well.
In the past decade, or so, steam has been available from h/w/e machines, including some portables and made removal of gum easier and quicker, just requiring a wipe with solvent soaked cloth to remove residuals.
As with any form of cleaning / repairing / maintaining, it's down to the operator. How good they are at using available products, how fussy they are about achieving a high standard, how honest they are about their level of skill.
robert m