Pass Labs INT 60 VS. Primaluna Dialogue Premium HP VS. Arcam A49

I would disagree that using a tube amp with the Sashas is ’inappropriate.’
I had WATT/Puppies for 8 years, and used mostly tube amps with them, and this was back in 1987, when their impedance in the top octave dropped to 1.7 (not a huge difference than it is now, but still...). But for a more recent appraisal, one might want to read Art Dudley’s review in Stereophile, where he used Shindo monoblocks with the Sasha for the review and had no problems with them.
While I am sure solid state would handle the speakers more easily, Dave (Wilson) voiced no objective to my using tubes. This was when he and I were both California-based (his factory was in Novato, CA, about 30 minutes from San Francisco) and I was one of the earliest customers. From what I see, the Sasha now drops to 2 ohms. And one of the principals at the late Fi Magazine used tube amps with his WATTS as well. I heard no problems.

I understand the concern, but it’s not really verifiable without listening. Some tube amps will crash and burn, but certainly not ALL of them.
Why don’t you simply call Wilson Audio and just ask them if THEY have any objections if you ever want to acquire a Primaluna? They’ll tell you outright so you can at least continue to consider it or - if they object - remove it from consideration.

Unsound, you’re probably right about manufacturers hedging their bets to make a sale, but, sorry, Dave states his thoughts on whatever amp the customer has, if he’s heard the amp. Or at least, he used to. I always found Dave to be quite honest, both in his estimation of his products and other manufacturers as well. So, what might apply to others (in your statement) cannot be applied to Dave.

 I didn’t ask Dave’s recommendation for an amplifier when I bought the WATTS. (I knew what he used to design the WATTS: Goldmund Studio turntable, Rowland Coherence 1, Spectral DMA-50/Rowland Model 7s, MIT cables. ) And I already had a Rowland Model 5 when I first got the WATTS. And then got VTL 300s, later adding the Goldmund Mimesis 9.

I use my own ears for listening, not the manufacturer's, and when HP wrote his review on the  original WATTS, I could only nod my head in agreement on every point he made, and he was using the Goldmund Mimesis 9 amp. Since I had both a Goldmund Mimesis 9 as well as VTL 300s, as well as the Rowland I didn’t have to "figure it out." All I had to do was listen, and, aside from the Mimesis’ phenomenal resolution and airiness, the VTLs - aside from resolution - revealed everything the Goldmund did, and were superior in bass power (which doesn’t mean that much to me, but it was obvious, so...). The Rowland was great, too, by the way.

(SOME) tube amps will work just fine with Wilsons, as will SOME solid state. Sonically, the VTLs had no problem with the WATTS (the most difficult of all Dave’s speakers to drive, especially the first generation WATTS), which I kept until the Series IV WATT/Puppies. And since I’ve had actual long term experience with tubes (VTL, Jadis, VAC and CJ (not such a great pairing), perhaps that can assist those interested in tubes.

The ONLY way to KNOW anything is to try it Everything else is sheer speculation, and speculation can cause more problems than almost any other factor.

You speculated on tube amps and Wilson speakers, setups you have not had the experience with and I have. Extensively. Even in science, one does the experiments to PROVE the result.  Your response  in this particular matter IS  speculation, because, according to those principles and physics, the WATT isn't a good match for tubes.
The REALITY, however,  is that Wilsons DO work with tubes. So, whatever principles and law of electrical engineering apply, they still do not negate the reality of the fact that Wilson speakers work with tubes. The "why" might be interesting, but if it works, it works. And they do. I'd expect them to be much easier to drive now than 30 years ago.