They’ve recently killed i.Reddit and /.compact (the mobile versions of old.reddit) and have also gimped old.reddit immensely over the last year, with things like images being force-embedded into the new layout even if you access the raw image path (!!), among other things. There’s absolutely no way old.reddit lasts much longer.
I use the old.reddit desktop mode on my phone. I can see 20 stories at once compared to 4 on the normal mobile layout (The text is small but still pretty readable). The minute they get rid of old reddit I'll probably just stop using the site.
Mobile reddit takes minimum 5 seconds to load on the latest Android using a fork of Firefox called Mull. I suspect the slow load is retaliation for preventing analytics, under the guise of "this script is waiting for a response, won't time out immediately". I'm always confronted with a "this experience is better in the app!" pop up. Signed in on old reddit.