Long back when I started my career in 2002-2003, we used to TRY read Roger S Pressman - Software Engineering (it was a too heavy book). Waterfall engineering was all around the world be it a small product, a BIG product, Fixed bid small product development or complete lifecycle long tenure product development. The agile was slowly gradually stepping up and trying to create its space.
I, like anyone else, even today was a BIG fan of waterfall software engineering, we used to learn for interviews the 5 step process [ Requirement -> Design -> Implementation -> Validation & Verification -> Release ] that's it and we used to start happily and end happily. Now, in today's AGILE world, since last 8-10 years this Agile has started squeezing like anything from 6 weeks to 4 weeks to now 60% of the product across the world has started following 2 weeks cadence. I am though not a too fan of this small 2 weeks sprint cadence why so because you need to be very disciplined, when I say discipline it means you need to have a well-groomed product backlog, so groomed that it is just a matter of smooth implementation when the sprint starts, the dependencies need to be clear right away, the team needs to be self-driven self-sufficient, ready to upskill themselves since the technology keeps changing every year. If all these disciplines are NOT in place, you all suffer, from product owner to scrum master to team members. If you keep this discipline, Agile becomes awesome process and which is demand of the time as the ideas need to market timely at the same time adapting to evolution.
One of the beauties of waterfall engineering was its documentation and good onboarding plan, nowadays industry is suffering from 90 day’s notice, engineers are playing with their skills and exploring multiple offers and confused as to whom to join, what they will do in 90 days, obviously looking for an opportunity which is Ok. In our days, we used to have just 15-30 day’s notice in India, still working on BIG products. Have you ever thought how?? We used to have a good documentation and onboarding plan, we could very well train a new engineer in 3-6 week’s time with a good training and onboarding investment which is missing in almost all Agile products these days and organizations have no option left then to hold engineer for a long 60-90days notice, sad in my opinion. I want to cut this short to limit the words but is an interesting debate, I have just thrown my thoughts, just think around it when you have some good time!!!