If you look at Lego Space during the 90s it is a long list of new versions (almost yearly) each with their own specialized parts.
Personally I don't feel like this narrative about a substantial shift in Lego sets fits with reality. To me it feel like people conflates it with the rise of licensed sets.
For what was a very small and cheap set at the time, you are getting 3 minifigs and a small building on a baseplate. The bulk of the parts are yellow- and white-coloured bricks for walls and architectural elements. There is a specialised yellow-coloured edge panel with a red brick texture, but it plays very nicely with the rest of the parts architecturally. You can easily combine this set with the bigger forts and harbours. The colours are compatible, the parts are compatible.
This is not certainly the case with modern Lego sets.
Weird ski bricks, seethrou chain saw, antenna, big arrowshaped structural piece, etc.
I'm not surprised the one you linked is from 91. Noone is disputing that the complexity rose from the 80s. But the complexity we are seeing now is not a new thing. It started in the 90s.
Some of the late Ice Planet (dunno the real name) space stuff from that same series, and some of the underwater exploration sets from IIRC about then or a year or two later, are specifically what I think of when I think "where did lego start to go wrong?" I kept getting them for Christmas and kept building and playing with them but the 80s (through very early 90s) themed sets were peak for those, IMO. I never did as much combining and modifying/expanding with those later sets as I did with earlier ones. I was still playing with the earlier ones and changing them to other things and combining them when I had those later sets, but the later ones could only really fit in if they could do it whole and as-is, that is, the earlier sets had to change to fit them, they couldn't really do the reverse.
... I don't think that era was especially complex, though, and in fact when I think about the worst sets from that era they were ones that were built with like half a dozen huge pieces for the bulk of the structure (there was some kind of Ice Base from that same series you linked that stands out, in particular).
Complex is the modern sets. Fiddly, even. Look at the size of a finished largish modern set (for kids, not one of the adult stick-it-on-a-shelf models), and its part count, and look at similar-sized sets from the 80s through, I dunno, maybe '95, and see what their part count was. The modern sets have so many itty bitty pieces. 500-something piece sets used to be really big when assembled.
The ski bricks are standard technic skis. The chain saw and is found in the entire series of kits. The arrow shape plate is a very common piece in all space kits back to the 1980, though the usually were grey or black. Often used for wings with hinged plates. I have literally dozens of those in my childhood lego collection. Antennas were on each an every space piece, though the thin and slender ones only started showing in the early 90ies. They’re still around.
Afaik, lego went through changes. They had period when then introduced a lot of special parts (I think nineties or so) and then period when they simplified again.
They introduced special parts at the height of popularity and money success. Simplified when they had money issues - simple parts are cheaper to manufacture. Now that they are popular again, they are having more special parts again, but still less then used to be.
Personally I don't feel like this narrative about a substantial shift in Lego sets fits with reality. To me it feel like people conflates it with the rise of licensed sets.
https://en.wikipedia.org/wiki/Lego_Space