What Sonically is the Difference between a $1,500 CD Player and a $10K-$25K One?

The way they sound. One of the things to consider is the system and the room. It is likely that a person owning a $1500 item may not have the rest of the pieces and a room that will let the differences be heard. Now go the other way. A person who has a setup that includes a 10k-25k player would likely hear the difference if a swap out to the lower cost one was made.

I love all the folks that assure you that there can be no difference of any import.  Try some auditioning at an audio salon, and I'm pretty sure you will then know the answer.  IME you can get some very real, sonically significant and musical improvements as you go up the food chain.  But the folks pointing out the diminishing returns with greatly increasing price certainly on to something, as well as the crazy-quick and steep depreciation of anything digital.

Get out and explore with your ears.  That will tell you a lot.

I have an old Magnavox changer with a tube output. Suits me just fine.

The problem with 1500$ CD players is simple - they are not good enough. So people feel ripped off as a difference between 200$ and 1500$ CD player is sometimes very small. Magic happens at 3000-5000$ price tag. So, my recommendation would be, if you can’t spend 5000$ on your CD player, then buy any CD player. They are all pretty much same. But if your budget allows you to spend as much as 5000$ new (or 3500$ on second hand market) then go for EAR Yoshino Acute, Lampizator Big 7, Audio Note CD players. Those 3 brands will give you the best value for your bucks. You'll have all advantages of digital and very analog type of sound. If I could go back in time, I would buy only top gear right away (Atma Sphere amplification, Lampizator DAC and Devore, Audio Note or Quad speakers). I've spent a lot of years upgrading from one component to another (and loosing money each time). In this hobby the one shall simply take a mortgage of 20.000$ and buy the best gear he can get for that money right away. It's not different to buying a good car. For 1500$ you can get only a crap. But for 20.000$ you will have a decent and safe car you'll keep for many years.

@larry5729 - you are a bitter man.