Improvements in materials and manufacturing and FE design have allowed bikes to be made lighter every year, but the UCI race bikes for ordinary stages or TTs have got heavier. Aero frames with deep tubes are heavier than ones with small round tubes. Most people now have a power meter built into the crankset. Everyone now has deep section rims on ordinary stages. Transmissions stopped getting lighter when they added batteries and satellite shifters. And they're all 12 speed. And many people have got oversized jockey wheels. Which need longer chains. Everyone now has flat topped aero bars instead of round ones. So the UCI limit has led to bikes having more features and more toys. Which is great for the manufacturers. I can't remember the last time that anyone needed extra weights. Maybe on a climbing bike when they're determined not to be over the limit. But for an ordinary stage the bike might be half a kilo or more over the limit.
