it depends on skillset... 120 TSP is not the same if DR HA is 17+, or both defenses are 15+, or JS IS us 15+...
if you train 1vs1 for forwards a lot, then 120 is possible (but still very hard), and there is still question how useful is that skillset...
anyway, big u21 nations always had 110+ TSP players in their roster before the end of age 21... it's not that big difference now...
with faster training, now smaller nations can have similar players... like BIH u21 didn't lose for 2 straight seasons (consolation tournament and Euro u21 championship)
in my opinion, faster training is good for the game... in old system, you need 10+ seasons to create championship roster with training 3 or more players...
10 seasons is more than 3 RL years...
with faster training, you can do it in 6-7 seasons...
just like in RL, great players become great very early... they don't have to wait until 30y old to become franchise or NT players...