Asking for opinions on a about ballpark siding quote

I had a roofing & siding company out for a roof quote. Out of curiosity as I can’t do this yet, I asked for a ballpark figure on siding replacement. House was built in 1913, 2.5 story American Foursquare & existing siding is asphalt that is worn in spots (research after the fact-I think it’s insulbrick?). Anyway, I was told 24k to put vinyl siding over the asphalt siding. That seemed high, and isn’t insulbrick flammable? Shouldn’t it be removed? I shudder to think how much more that would be, but was surprised he didnt say the old siding should be removed.