Are you talking about 2.5" externals or 3.5" externals?
The 2.5" externals have been migrating to direct USB connection for a long long time. WD has been doing it for years, and Seagate started doing it now too (past year I think). I don't care about 2.5" drives though, I'd rather have a standard drive inside USB enclosure, but the 2.5" externals have always been backup/transfer drives for me, if one dies, sucks, but I don't care about data on that drive.
3.5" drives are completely different matter. Being able to buy cheap 3.5" externals and shuck them is a major cost advantage to me. I can buy 8TB external for $230, the cheapest non-shingled internal is $100 more. That's major cost savings even if you figure in shorter warranty. Are you saying you have seen evidence of 3.5" externals migrating to direct USB connection?
Both.
In this case, it was a 1TB 2.5", and a 3TB MyBook (I think that is what they call them).
They just bought those ~2 weeks ago, and the date stamp on the HDs showed 12/2016 & 1/2017, so it was a fresh batch.
Client (a Jeweler) wanted to copy over a ton of files, and they only had USB 2 and was way too slow for them, so I told them to open the case (they first watched the youtube vids on how to open them), and just hook it up to their desktop machine, when they informed me that the drives in question had no SATA port after they opened it.
Ended up telling them to buy a USB 3 card to use.
What I don't know is if the bigger capacity HDs (6/8TB+) are also going this route, I just assumed that they would.
Here is a video of the 2.5" ones that I found. Notice, no screws, just soldered on.
*edit, apparently, Jewelers have all the tools possible to open up anything, without damaging the tabs.
I was rather impressed when he got those opened without breaking anything.
I joked with him that he should offer his services to open cases for a fee.