Not much more to say besides what’s already been said. Optics never go “bad,” meaning unless they break they’re still totally usable. The trick is finding someone who still finds its features to be worth the asking price. As already noted, the G2B is a heavily dated reticle in “tactical”/precision circles, it’s heavy, big, and parts support for it is likely to be poor. Not sure if Steiner offers a lifetime warranty on them, I haven’t bothered to check.
Frankly, I like a lot of older optics. I think the classic USO SN3 is still tits with a GAP or Gen2XR reticle. But the catch is there’s absolutely no way I’m about to pay $1500 for one. I’d be very hard pressed to pay $1000, even. Maybe $750-800 or so if it had every option exactly how I wanted it and I had a rifle it “belonged” on. But when something like an Athlon Midas Tac will do everything these now-vintage scopes would do short of survive being dropped off a cliff, and will do it for half to a third the cost, the choice is simple. If I’m not jumping out of planes, I don’t need a literal tank for an optic, cool as it may be.
Hard pill to swallow, OP. Been there and it sucks, but you have to decide to just keep it forever, or keep dropping the price until it sells. Also, this is NOT a seller’s market right now, which surely isn’t helping you any.