While the US online Google Store obviously still accepts trade-ins as a convenient form of saving money on the Pixel 3a or Pixel 3a XL, the actual price cuts you're looking at now are almost negligible. Granted, you can get a substantial discount of up to $610 by giving up your "old" iPhone XS Max in favor of a new mid-range Pixel, but why would anyone ever want to do something like that?
Naturally, all good things must come to an end eventually, and these incredibly generous promotions are clearly no exception. It's also worth pointing out that Google has essentially aligned its official Pixel 3a and Pixel 3 trade-in programs, offering everyone the same exact discounts. You can switch from select Android handsets made by Samsung, LG, Huawei, and Motorola to a new Pixel as well at similarly reasonable but not quite mind-blowing markdowns.
Finally, if you don't have an old, fully functional phone to trade in, it might also be a good idea to check out the latest batch of Best Buy deals including sweet freebies and decent savings with upfront carrier activation.