I disagree that these are just being bought for collector's issues and not for performance. Many of these are being used as a basis for turntables that, to the ears of many, are more musical, have better timing (the previously mentioned PRAT), and are just simply more involving than some of what is out there new now, including a lot of the suspended belt drives. I would think that if it's just a collector's thing, they wouldn't be being modified, dropped into giant plinths, with modern arms. They'd be restored to stock..but they aren't being made stock. In almost anything I've ever collected, anything done to modify it from original condition lowers the price. That does not seem to be the case with the 301, 401, or 124.
They're being made to try to beat turntables costing much more than $1000, at least to the ears of those doing the restorations. High torgue, driving a heavy platter is the sound a lot of people really think is where it's at in turntables, and those with DIY skills, time, and maybe a nice arm laying around are buying these up because there aren't that many that were built like the 301 or TD-124. Even the Lencos are going up in price as more people hear what these high torque non suspended TTs can sound like, in comparison to what we were told for years was the only acceptable way to build a turntable..such as the Linn way. I've only heard unrestored examples of RoKs and Lencos (and my belt driven but high torque,unsuspended Empire 208) and there really is something to that sound. So much so, to my ears, that I bought the only modern interpretation of it that I could find for a (somewhat) affordable price, because I simply didn't have the time or work space to do a restoration. I'd still love to have a 301 someday.