After the introduction of digital cameras require a 'qualifier' to split between film and digital. Initially the 'default consideration' of 'a camera' was that it took film, thus the common need to search specifically for 'digital camera'. However time marches on, and social norms change. If you ask my nephews "How do you see photographs after taking them with a camera", they're going to describe looking at them on a screen. And if you ask them what I collect they're going to tell you "film cameras". [or 'old cameras'? I should ask them sometime...]
But more on topic...
Enlargers, being kind of large and hard to ship cheaply, are an item that gets into a neat sort of regional markets state, and are strongly affected by momentary market conditions.
Accurately judging price trends is going to be difficult, as there isn't exactly much in the way of a reliable tracking source. Prices shown on local used good listings may also be a poor test for the local value, as those can easily be "What's hanging around" that no one really wants to buy, and is quickly upset by something like someone suddenly offering up their darkroom in a "Take it away before I haul it to the trash" kind of sale.
And that is kind of the sad thing. Connecting those who have one they want to get rid of [and what little for it] with those who are looking to get one [and aren't willing/able to pay much] isn't easy. I had an old family friend offer me $200 to take an old 8x10 commercial grade enlarger off their hands a few months back. Sadly they hadn't heard I moved clear across the country... And I've not noticed a working enlarger offered for sale here in Victoria in the last two years, but I've also not been keeping too close of an eye out for one. [I don't really have the space for one currently.]
Of course if you want a working unit without worrying about how badly worn or abused it is, you can always just buy something new that is still in production.