The Taiwan made also has a VG1 core, not VG10 as you've stated.
There's a noticeable performance difference between VG1 and VG10, and VG1 isn't that great of a performer. Cold Steel used it on a number of their knives, folders like the Voyager series, The Gunsite series, the Scimitar, etc. They became available in VG1 but It was a lackluster upgrade from AUS8A, a minor improvement in performance but that's all.
VG1 now is not a steel to be recommended, but VG10 is a decent enough steel but not particularly special and it's used in some fairly cheap knives nowadays.
The Cold Steel San Mai Trailmaster should've had an upgrade of the core steel years and years ago. I would've been great if they'd upgraded it to S35VN, even S30V as that's still no slouch, but I believe that it was written into the contract with Ichiro Hattori in Seki city Japan that VG1 was to used until the contract ran out.
GSM Outdoors are just being cheap by sticking with VG1, it's just another display of how they're destroying the brand and not moving with the times.
If they'd upgraded to VG10 as the core steel, well that would've been something, but realistically it still wouldn't have been enough, not for the well informed amongst the Cold Steel collector and/or users.
I have collected and used Cold Steel knives since the early 1990's and since Lynn sold the company everything about the brand is going bad, which obviously is a crying shame but that's GSM for you, they're bean counters, and I'm being polite when I state that about them!