And it'll continue for decades probably.
That's part of the issue. "Doing X works for me" is anecdotal. A lot of the people who claim weights helped their cycling also admit to increasing their mileage. It's probably not hard to see where the real gains come from.
We can also research, and think for ourselves instead of swallowing everything pros print in books and mag editors send to print.
There are always some to rely for various reasons on gym work,prescribed or otherwise. When you look at how and when different muscle fibre types are recruited, how they adapt to stimulation, the energy systems they use, their inherent blood flow, their speed of fatigue. The science alone weighs heavily on strength training having very little effect upon aerobic cycling. The exceptions generally limit themselves to sprinters or track racers,two examples where explosive but limited anaerobic efforts reign.
Magazines, papers, books - sure those are a source. Lets discount them then assuming they misquote or mislead.
Another is the cyclist him/herself. The pro, elite racer or even keen amateur. The cycling coach or the team trainer.
Point being that all of these positions may tell you that weight training is beneficial for some types of cycling. Perhaps for extra explosiveness in a climb or that sprint at the end of a race. Maybe it is to raise ones power to weight ratio.
Whatever the reason, some of the best riders in the world do weights. Some of the best cycling coaches in the world tell their riders to do weights. Now you could assume that they have done some research in to the matter and that is one of the reasons they are at the top of their game. Team Sky leave no stone unturned and several of their riders are on weight specific training.
What i disagree with entirely is the 'what works for one works for all' idea that is sometimes put across. Exactly the same with dieting. Sure there is a starting point that will serve you well but after that it's up to the individual to discover what does and doesn't work for them.