"When I get ahold of a
firearm I like, tend to keep it, not sell it.
See what I mean? "
You, sir, are out of tune with modern gun buyers...same as I am.
I am not a gun collector, gun trader, gun seller, gun tinkerer, just a shooter and instructor.
I have used the SW/SD Sigmas as loaners/trainers for 2 decades, and in stock form they are rugged and reliable. They don't lend themselves to mods and not much aftermarket bling is available. The SDs were developed to address the myriad trigger complaints about the SW, which is discontinued. The SD9VE is a cheap service pistol that stands up to abuse and use, not a "platform" to constantly "upgrade." And as hoc9sw pointed out, there are more sellers than buyers for basic pistols: around here $150 is top for a used Sigma.