That’s cool. Congrats on that by the way. You’re highlighting my point (in 1992 - looking at 40 to 75 grams).
Your reference “Recommendations for carb intake during exercise” recommends 40g/hr for a 2 hour event. The current world record marathon runner (Kipchoge 2:01:09) is taking in 100g/hr. Talk about gut distress. A freaking marathon!
Fajitas are a “traditional” Norwegian lunch? 
You seemed to have missed the part that I bolded.
You also seemed to not understand Asker’s academic standing. He’s far more of an expert in this area than Kipchoge’s primary advisor, i.e., Andy Jones (and if you read Asker’s site, you’ll find discussion of high rates of CHO intake in runners…what’s still lacking, though, is definitive evidence that such high rates benefit performance compared to lower rates).
As for Kipchoge himself, he still drinks beet juice, so I don’t think you should really be looking at what he does as your guide.
Regardless, the point still stands: the answer to the question you’ve posed is clearly “no”.
Unless you were working in the pro peloton in the 1990s, how would you know? I’ve been racing and following cycling since then and that was never really talked about not in exact details.
I seem to recall that the feed stop, musette bag, and lunch on the bike was a much bigger deal in the 90s than it is now. I suspect they have traded a lot of that for gels.
Are you serious? Check out any cycling training books from that era (Carmichael, Friel, etc.) - it’s all in there.
What was in books and what was done while on a bike in the Tour are two very different things. Those guys constantly eat. Did anyone ever count the grams of carbohydrate back then?
In any case, probably not the biggest performance leap of the last 20 years. These guys are now breaking doped records from the Pantani/Armstrong era. It’s not just aero bikes, power meters, scientific training, and some extra CHO.
Regarding the TT and at the risk of going severely off topic, I couldn’t care less if they were doping. It’s exciting as hell to watch. Let them dope for all I care.
To the original question, I think it’s similar to building a superlight bike. Some grams here, some grams there. They all add up. It’s likely a combination. Bike are lighter and faster. Talent is identified and trained at a younger age. Nutrition on and off the bike. Recovery. Power meters are cheap. And genetics. Now you have a few generations of athletes building on the base of the previous.
Unless you are working in the pro peleton in 2023, how would you know? LOL
What constitutes definitive evidence?
Certainly more than a couple of studies, that’s for sure. Especially true when the study design is suboptimal for testing the hypothesis.
"Ask good questions. Attack with rigor.’
This is funny, I got to revisit this a bit. Back in the 90s/early2000s they had wind tunnel testing, power meters, physiological testing, best sports scientists and doping plans like blood transfusions and micro-dosing (Dr. Ferrari et al). And you think they sent them out there w/ a couple of baguettes w/ no idea or plan to optimize nutrition? LOL.
LOL that’s my nutrition plan, but forget the meat when doing VO2 intervals. 
I am sure great nutrition has something to do with it, however, sadly, plus ça change, plus c’est la même chose…
So, they had all that but somehow today on bike nutrition is a performance leap? LOL
Per the original OP, of all the (legal) improvements to training, bikes, aero, etc. - is this the most significant? I think it may be because it allows them to train and race harder. You understand the critical issue of glycogen depletion over a 3 week period (tour) on performance and recovery, yes? So when you increase in-race consumption of CHO by 70% (not including keytones) - would you think that would have a significant impact on performance over a 3 week tour?
Just watched that this morning and if you missed it, this was from last week via @plaursen Everything You Need to Know on Ketone Science & Supplementation - With Dr. Chiel Poffé - HiitScience The last point on the show notes was the most interesting to me.
If it wasn’t $35 bucks a bottle which is what they used in the protocol I’d love to give it a try. I bet most of the top teams’ riders are taking multiple bottles daily along with the high altitude training camps and dialed in nutrition and fueling. Actual banned PEDs are probably cheaper than exogenous ketones.
You should edit and add this to your OP.
