30 years ago you could do a lot with 8-16 mb ram and no internet connection.
Nowadays... unplug a modern computer from the internet and it's mostly useless.
Want to write a simple document, using a basic word preocessor? You're going to need at least 1GB ram, mate.
VisualBasic allowed writing GUI-enabled applications that would be essentially be standalone, shipped as executable files sized at (usually) less than a megabyte that would mostly "just work". Nowadays most people write GUI app in the form of frame-less web browsers displaying html and running Javascript, requiring more than one cpu core and 2-4 GB of ram to be barely usable.
Yeah I definitely can see how "The quality of your average tech worker has completely nosedived in the last 10-15 years".
As a system engineer... I have worked with some developers that constantly had memory issue ("I need more memory to run my containers, please increase the memory quota in the (kubernetes cluster) namespace") and reasoning about memory was just a non-existant skill. They just had no idea what was using memory in their software. Literally, their ass was mostly saved by the fact that process management nowadays is "good" at restarting software and managing retries on failures. Knowledge about the underlying operating system was also very very basic.
Such people, while surely filled with good intentions, were mostly useless without some random Medium article instructing how to apply some generic fixes, or without some stackoverflow question covering their exact use case.
But wait, it's way worse than this. There also are people that got promoted to managers, don't have a solid technological background (besides the little coding they've been doing before being promoted) and just can't understand the willingness to optimize and "geek out" on performance issues (and the value of such activities).
Oh and don't even get me started on nowadays a "senior developer" is somebody that is good at "delivering value to customers" instead of somebody that knows the ins and outs of the problem domain and has mastery over the technological stack.
Working in tech nowadays is a lot less about tech, it seems.