Honestly, I really do not understand that wide cost variance in various CD players unless it's all about the DAC.
In some cases like Wadia (at least back when they were still making CDPs anyway) and such much of the money was more on the rest of the hardware as these are giant, overbuilt CDPs or CD transports (whole unit but only has digital output). In some cases even use CD transports (just the mechanical subsystem that spins and reads the disc) that Sony etc does not make at high enough volume (ie they're not even the bare units used in, say, high end car receivers or stock receivers in some luxury cars) such that Sony etc sells them to the hifi manufacturers per unit at that volume level being equal to the price of an entry level hi fi CDP (that said, some like Arcam, IIRC, even used a DVD-P that was otherwise available in some 5.25in computer drive bay DVD reader).
Regardless of the price of the CD transport subystem, manufacturers build an overbuilt chassis around them to protect against their own vibrations and all the soundwaves that very large, high end speakers ie the kind that people blowing $5,000 on just a CD transport would likely buy, leaving as little as possible for the error correction of the transport to the point that even a Rolls Royce Phantom's (ie the car with the most ridiculously overbuilt suspension system for managing road irregularities as to prevent champagne from spilling as you drive over a gravel path) CD receiver would be almost like a WalMart DVD player next to it.
And then there are the secondary costs. Heck if you're making a heavy AF transport or CDP that you'll get charged for, heck, might as well build it into a heavy milled aluminum chassis that adds much of the weight for stability (on top of the dampening on how the transport is coupled to that chassis) as well as making it look the part of what money you pay for it (like speakers that get a cabinet with reinforcement and finish worthy of a grand piano, or how when you buy a handmade knife made entirely by at most two to three guys each you get a real hardwood handle with a smooth finish that even fits into a steel ferrule instead of a molded wood pulp handle). But by that point the CDP or transport unit is already expensive, but being this large and heavy, now you have to put it in packing material that would prevent any damage from shipping, which is more expensive (some even arrive on a crate; I heard of a guy who had his power amps delivered at his home in Manila by the guy who designed them and carried them as airline baggage himself, and one other guy who had to call in his friends to get a crated Krell amplifier up to his audio room) on its own, then add how much they ship due to weight and how you can fit only a few of these in each container, plus dealers that have to have a healthy profit margin both for the low volume as well as to cover employees' insurance when handling such heavy equipment.
It's basically the same thing with those huge TTs, especially the ones that come with three tall, mass-loaded legs that not only keep them stable but keep the user from setting them on a glass top that might break or bending down too far every time they have to swap out the vinyl.
Personally, you can avoid the vibration issue that makes any heavy mechanical equipment (and not even
that heavy) by just not using mechanical parts. Like a smartphone or DAP with an SD card. Or a miniPC with a low voltage, low power, passively cooled CPU with SSDs.
