i've mostly had this opinion that if the routine is more or less sound, it doesnt matter which one you follow, they will produce results - its the other factors which will come to play even more, from, diet and rest, to life stresses, training partners, position of moon and availability of druids and crystals - in other words, who knows...
The psychological factors are hugely important though - if you believe that THIS routine produces results, it has a higher likelyhood to do so
For me the biggest factor is my surroundings and training partners. Everything else just supplements that.
So therefore, your conclusions seem rushed. Sure its easier to make strength gains with weight gains - though then you could say you are not making much relative strength gains anyway
But time and time again people from all kinds of strength sports show that you can make solid gains without the weight gains. Even on this forum we have many people who have proved it - hey i guess i am one of those since i have been in the 105 class for few years now