Another 40 year old here: I mostly agree and I've also found that thinking deeply about a problem for a long time before trying to build anything pays huge dividends. In particular I spend a long time thinking about how I can simplify the design to save implementation time, which means actually building it is faster. I also think a lot about UX and DX: simplifying installation, interface, maintenance, removing unnecessary knobs, choosing the right algorithms and tooling, etc.
I think waterfall style development works for one person inside one's own mind, but not beyond that.
A lot of the stuff I see from 20 year olds these days is monstrously over-engineered and Rube-goldberg like. Many keystrokes, sure, but less thought. This also yields bloatware that hogs resources and is hard to install and maintain.
http://www.ariel.com.au/jokes/The_Evolution_of_a_Programmer....
More thought and less typing young padawan.