I disagree with that statement. I've seen decent resale on normal equipment around my area with grizzly. Now a 5hp shaper has a pretty small market, so I suspect you'd have had a similar situation with most 5 hp shaper brands.
Much like the resale value of 3 phase equipment is crap, not because the product is bad, just because the market is much smaller.
Resale value is directly correlated to the size of the market available. If there's only one guy willing to make an offer, well your going to get what he offers you, if there's 10 guys chomping at the bit to buy your used 3 hp table saw, your resale is likely to go up.
The tools don't make the craftsman....