You can alter the definitions to suit your claim that Palladium is the oldest surviving RPG company
I said oldest "OSR company" but without needing the R...not RPG company. It was a claim they are the oldest producer of a specific subset of RPGs, not RPGs in general.
even though Iron Crown has been publishing Rolemaster since 1980, Chaosium Call of Cthulhu since 1981, Hero Games Champions since 1981, Flying Buffalo Tunnels and Trolls since 1975, etc. I grant you that Palladium is pretty unique on that KS has been doing his thing continuously since 1983 or so, as both a creator and a business owner with an actual staff and physical premises the whole time. The only real peer there is Steve Jackson, since 1981 although not exclusively an RPG company.
(I won't even mention FGU, which technically qualifies and last time I checked was still in existence. That's one guy in a home office who bought some games from their writers in the 80s and stubbornly holds on to the copyrights.)
Now, ICE is something more comparable to the actual claim I made about Palladium. They have stuck to pretty much the same system which represents what I'd consider old school mindset about games.
Not sure why you're mentioning CoC for Chaosium in this context as Runequest, essentially the same system, is even older and was in your first post.
While I've been playing with Hero, through Champions then Fantasy Hero (which was the D&D replacement for one of the two groups I was in my last year of HS and the one I told to college with me) I don't consider it an Old School system, but a representative of the changes coming in the 80s. While I group GURPS with Hero in that sense, The Fantasy Trip is more like a hybrid step between the two mindsets.
Again, FBI has had T&T the whole period and competes in that sense, but T&T pretty much stalled sometime in the mid-80s and FBI focused on their core business, computer-moderated PBM games.
FGU is a weird case, but I'd argue qualify even less that SJG simply because of what you mention: sitting on copyrights and stock but doing nothing to create new products or bring in new fans most of the intervening years.
The reason that I mention that CoC has been published continuously by Chaosium since 1981, rather than mentioning Runequest, first released in 1978 (I have the first edition on my shelf) is that Chaosium did not publish it for a long time prior to regaining it in 2017.
As far as "OSR" vs RPG, it's meaningless to me, I don't care for the OSR as usually defined as DnD clones, and you're not using it in that sense anyway. Is T&T OSR? Runequest? Call of Cthulhu, which has the same engine as Runequest? Rolemaster? I couldn't care less.
Also, Flying Buffalo continued to publish T&T supplements through the 80s and 90s, and released 5.5e sometime in the 90s, then 7 and 7.5e before Deluxe. (No 6e!) So I guess Ken St Andre will be crying onto his cornflakes that this "pace of development" didnt meet your arbitrary requirements.
Anyway, we're all agreed, Palladium are one of the few remaining dinosaurs preserved in amber from the early days of the hobby. It will be a sad day when Kevin writes his last Stan Lee-imitation hype screed and promises an exciting "coming soon!" for the last time.