I would think used sales quantities would be more of a reflection of a manufacturers time in the marketplace, their percentage of market share, rapidly evolving features desirable to competition and government regulatory changes than any quality issues.
Some of these brands have been around forever so it’s inevitable that some would be up for sale.
Some have sold so much volume that you know used sales will result from impulse purchasing.
Look at how fast various rifle disciplines have evolved...a high end scope 2-3 years ago is easy to be talked into replacing for the newest kid on the block.
And as fast as the Liebrals started their sh#t many people have put up some rather expensive optics for obvious reasons.
What I get a kick out of is this is the first forum based on elitism...I would have bet it would have been shotguns first...
Who knew optic snobs were the leader of the pack, lol...