Lots of good points being made, but the over-arching issue is the market just isn't there anymore. As I've written before, I see the market as an inverse pyramid with auto enthusiasts at the wide-open top. Then as you refine buyers down, such as high performance buyers, to muscle car buyers, to 1960s-1970s buyers, to Mopar buyers, to those who want say a 383, to those who can afford shipping or pick-up themselves, and on down to those who meet all those qualifications AND are willing to pay your price, the market gets really, really small. And now that the investors are bailing out of the restoration business, and we return to an enthusiast-driven market, the market gets even smaller.
Back in the late 2000s, 440s and 383s were selling for close to $800 for a bare block, now I was able to get a 72 440 that had crank issues but came with a Holley intake, Mopar Performance valve covers, Mallory ignition, headers, a 727 tranny, original exhaust manifolds, a Thermoquad, and a MP Purple camshaft and lifter kit for $200 out the door. The guy who was selling all that for $200 got my money. The guy selling the 75, needs-rebuilt, 440 from a motorhome and wanting $500 firm didn't, and he's still listing that engine a year later while other 440s listed for less are long on their ways to new homes. This is the big issue with the current market. The low-hanging fruit on the pricing tree is sapping all the cash out of the market before demand can get high enough for higher-priced parts, and absent all the resto dollars, there are now more parts than buyers to buy them.