Reddit has a long track record of incompetence. The site has historically been very unstable and their attempts to replace the front-end UX for both the browser and mobile apps have been widely panned. Therefore, it's reasonable to suspect that they be making a mistake with this decision as well, despite having access to all of the relevant data.
Put another way, Reddit began enshitiffication no later than the "new" style and since it's intentional, it's only a mistake in the medium and long term, as has been noted they're trying to squeeze a few bucks out of its hulk before it dies.
