Yeah, I like these classic old styles.
Part of the reason there is 158 different WT jerseys might be found in the manufacturing methods.
The "old school" knitted cotton rugby jerseys could only incorporate straight lines of colour change or stripes, etc. They could only knit horizontal changes into the fabric. If you needed a vertical change, you'd have to knit it horizontally and cut it out and turn it vertical and sew it in.
You could not do colour graduation change, background colours, curved designs, etc.
The more recent lightwight sublimated jerseys can have limitless colour/shade/blending changes on them. A logo can have a bloody rainbow on it, and turn out looking fantastic. This was simply an impossibility in the old days.
SO . . . . . now that the technology is there to make a kaleidoscope of colour variations on jumpers . . all at reasonable manufacturing costs . . I guess the clubs can't help themselves.
Churn out a new jumper for any obscur reason, and the punters will still buy it !
Plus . . . more $$$$ from those of us that just have to have the lastest jersey.