Newer is not always better. We live in a capitalist economy and new products reflect the wishes of the consumers. Most consumers nowadays want new features, better screens, light weight, smaller form factor. Since a good ear must be trained, most people can't tell the difference between a high-quality and a mediocre chain when it comes to audio recording.
Most consumers are music enthusiasts or podcasters, or videographers. The portable recorder market really took off with the advent of DSLR video. This is a market to which Zoom catered with a very good foresight 13 years ago when the original H4 made history, because its main competitor, the M-audio MicroTrack failed in many respects (internal battery and lack of internal microphones and XLR connections being the main culprits, in my opinion). At the time the only cheap alternative was the minidisc with many disadvantages. On the professional side there was the DAT, but much more expensive.
With that said, I bought a second-hand 744T three years ago and made a lot of money with it. Never serviced it once, even though the buttons don't work very well and the screen has some black lines. Recently when inquiring about servicing I found that this recorder was made in 2005. 13 years of use out of a 4000$ recorder is exceptional.
Sound Devices still offers the 702 recorder. And the 788 as well.
My advice: buy the 744T. Build quality is outstanding.
Fun fact: at a low-budget shoot I took a short bathroom break, and left the sound bag on the grass, with the entire team standing near it. A stray dog came by, sniffed the bag and... you guessed it... took a short bathroom break himself over my 744T. The crew quickly stopped him but a tad too late... in any case when I returned I turned it off of course and removed the battery. I used the backup recorder for the remainder of the shoot. When I got home, I opened it up, cleaned it out thoroughly, and let it to dry for 5-6 days in the sun. I put it back together and the screen was showing nothing... but when the 744T warmed up, the screen started to show again. After 2 weeks, when the screen dried out as well, it worked perfectly even when cold.
And it still works to this day.
Try that with a Zoom!