Bad time to sell anything, but that really has little to do with it.
The item your'e selling is a bit of specialty item that is hard to find, and has a high cost. It has limited interest. There aren't many people out there looking for the RPK variants, compared to looking for the "regular" AKs. Those that are out there looking for them understand what they cost and that you generally can't just buy one retail, and have probably already bought a parts kit or whatnot.
As you know, these more esoteric builds generally don't happen in a day. You get the urge to buy/build, you start collecting parts, you send it off, etc. It's a process that usually takes several months. You need to find a guy right at the perfect time, and you have to have exactly what he wants. If he doesn't want your exact variant, he's going to build his own, most likely. You need to find the guy that not only wants to buy/build an RPK-74, but is willing to pay what they cost, and has not already started the build by buying any parts (because if he already has going forward with his build will be much cheaper), and who wants something close to what you're selling. Also, if he thinks he can complete his build for less - he will probably try to.
And let's face it, we're talking two grand. That is a LOT of money for any AK. A determined person who wants an RPK-74 can probably get it done for less than 2 grand.
Here is one for sale for a grand
One for $925
Buy-it-now for $1400.
2k just isn't realistic. There's just a difference between having one built for 2 grand and selling one for that price.
It's not just limited to AKs, either, in any hobby field, collector cars, or whatnot, that's just the way it usually is.