Post Vietnam era forbid physical abuse of recruits but that's about all that changed. Physical and psychological pain through PT is still highly encouraged and in full effect!
Technology advanced and training evolved only enough to embrace the technology. The Marine Corps Martial Arts Program is one great example. I went through P.I. in 1985-86 and will be first to admit that the hand to hand combat we were taught pales in comparison to what it has become today. Another example is final phase field exercises. Mine was nowhere near as strenuous or intense as todays 56-60 hour Crucible. Todays Marines are, in my opinion, the finest combat warriors in the world. Their training is better and their toys are better. I don't think there's another standing army on earth that compares head to head.
Rest assured, the USMC has always been and will continue to be Americas premier fighting force, ready to put war at the front door in 48 hours or less. Recruit Training will never be considered a walk in the park.