whats the problem with GMCs???

[ol yellow 72]

ive had my ol 72 up for sale locally for about a week now, and have had 3 people look at it and all 3 have told me "if it were a chevy, id be all over it", so could someone pleae tell me why it seem no one like the gmcs, i have had 2 and im not a huge fan of the 4 headlights, but other than that i see no real difference at all, plus i liked the fact that u dont see as many GMCs so if anyone has had this problem, or knows y please chime in, im to the point where in thinking of just trading the doghouse with a local yard here and making it a chevy to try to get a sale.