Training is like most everything in bodybuilding, it goes along with a trend. The trend is usually associated with whoever is Mr Olympia or, in recent years, whoever is very popular.
We had Arnold and training was thought to be hours in the gym, tons of volume.
Then it stayed in that lane until Dorian came along. Dorian is a special case because during his time every other notable Bodybuilder was still leaning on the high volume approach. What he did in terms of training was thought to be pretty outside of the box with some outlyers like Mentzer and hit training.
When he stepped on stage in 93 it was undoubtedly the biggest change in a reigning Mr Olympias physique ever. It was undeniable that what he was doing in the gym was working and we've got blood and guts training.
Few years down the road along comes Ronnie. Ronnie is special too because, NOBODY could do what Ronnie did. Unimaginable weights for not only high reps, tons of volume. Training started to shift back to the higher volume.
We stayed on this path for pretty much twenty years or so. Jay, dexter, Phil and even Ramy now.
What HAS changed is the influence of social media though. Now we're seeing popular guys with amazing physiques such as Hunter Labrada, James Hollingshead, Ian Vallier, Martin Fitz, Nick Walker, Jordan Peters and many more who have reverted back to the idea of much lower volume and higher frequency, heavy loads, gut busting sets.
I personally prescribed to this philosophy as well. The guys who are freaks will grow doing whatever. I think the difference is, us less gifted individuals really thrive on the low volume approach. I believe this has also given rise to a larger number of quality physiques overall. You don't have many shows now where there is a clear cut winner, the second group of guys are getting better and better and the gap has closed.
To this point, with the higher frequency lower volume approach, intensity techniques are used more and more.
To smartly put together a program, knowing when to use these during the session and which ones to use can REALLY make a huge difference in continuing to progress OR digging the recovery hole too deep given the frequency and volume you're using.