i guess his point was that the V4 manufacturers most likely will just downsleeve their existing engines for cost reasons, while yamaha can and should build a new engine that is narrower (even if it is one inch), which brings them that much closer.
Developing an all new V4 engine means at least 5 years to be competitive as KTM has shown, even Aprilia's switch from 60 degree to 90 degree was about 3 years in the making, and took another 1.5 years to be competitive. I don't think Yamaha can afford that. If they wanted to go down that road, they should have started the project during Rossi+ Lorenzo 2.0 , IMO.
More worrying about Yamaha is what Simon Crafar shared a couple of years ago on air. Apparently, when they changed their air intake shape to chase performance, they also ran the intake through the headstock (vs around it), which completely killed their front end feel and corner speed machine status. They’ve managed to get some of it back, but not all of it. Which is incidentally one of Quartararo’s main complaints (As well as Rossi’s, in his final seasons).
Maybe aero will help mitigate this. Maybe not. We’ll see.