My view of sim play is mixed. I think the idea of relying on mechanics to specify outcomes of declared actions, by modelling/representing (in some fashion) in-fiction causal processes, is a real aspiration (I did GM Rolemaster near-weekly for about 9 years, and then near-fortnightly for another 10 - hundreds of sessions, and thousands of hours of play). That RM experience also makes me acutely aware of the limitations of this aspiration, and all the ways that it breaks down as soon as the fictional causal inputs become complex in terms of space, time and number of participants. (It's not a coincidence that RM will resolve climbing a typical wall fairly handily, but punts to the GM when it comes to climbing a mountain; or will handle a single negotiation fairly handily, but punts to the GM when it comes to working out what sort of vengeance a wronged faction might wreak upon a group of PCs.)This is also the way I see it. Although your view may be more nuanced than mine.
It could also be that there are two camps or approaches to rpgs and we're really talking about what separates them.
I'd like to think that the three hall marks of post-Forge design are:
Intentionality and also therefore
Integration of mechanics to fulfil purpose
A rejection of 'mindless' accretion and tradition.
But it may simply be that I (we) don't buy into certain principles of the other camp. I'm thinking:
Adventure paths, rejected on either aesthetic grounds or on the basis of agency
The idea of sim, rejected on the basis we don't think it makes sense.
Sim rejection is also interesting because you could (and probably do) have groups that identify as sim but the actual techniques used are basically Narrativist. In which case the rejection is far more complicated. The big difference really being that Narrativism with a modern ethos finds game state consequences and disclaiming decision making a fundamental part of conscious design, where it may be intuitive and unconsidered in Narrativism encountered in the wild.
Porting certain approaches back to older games. Such as what you're doing with Traveller. Suggests it's very specific intentional approaches that are legit rather than intentionality itself. I mean Robin Laws approach to good games mastering (for instance) is intentional, it's just one we reject for being stupid.
Another issue with sim is that it (i) consumes time at the table, and (ii) focuses a lot of that time on stuff that is often not inherently exciting. When it is working - and see my previous para for a sketch of some significant limitations - it does disclaim decision-making, but at a fairly high cost. My RM play I regard as vanilla narrativist (in the Forge sense), but with a lot of accreted sim baggage that didn't really serve the narrativist purpose. This is why, having discovered systems like Burning Wheel and Torchbearer that have a high degree of overlap in terms of sim-y PC build and mechanical elements but that don't have the same sorts of punt-to-the-GM-limitations, I would not go back to RM. Even though it does have very colourful table results, especially for crits!
You comment on narrativism "in the wild" is interesting. I've been in two minds about it for the past two decades. On the one hand, I can't imagine that my experience with RM was unique. There are so many RPGers, that surely others have approached play similarly.
On the other hand, though, I've only encountered a tiny handful of people (like, fewer than half-a-dozen) who look at their sim-y play (in RM, or RQ, or HERO, or whatever) and recognise it as vanilla narrativism (or otherwise aspiring to something like that). So whereas, when I encountered Edwards's essays on sim and on narrativism I could see that he was talking about RM (purist-for-system) and had diagnosed some of its limitations (eg his insightful stuff about initiative systems), and in his discussion of narrativism was also talking about something that made sense of my play; I've found that most sim-inclined people reject all of that.
And in discussion, rather than identifying sim design as one way of disclaiming decision-making, they tend to double down on the authority of the GM to decide what happens next and to eschew any idea that consequences of declared actions should have any meaning or significance other than reflecting the GM's view of what "makes sense" in the imagined situation.