I would agree, I would also add that generally programmers today are not used to dealing with the memory limits of '80s computers. What is now considered an embedded device, back then was a desktop. My smartwatch likely has more memory than a PC Jr.
No idea what smart watch you have but the latest (series 9) Apple Watch has (up to) 2 GB of RAM and 5 Tflop of computing power, while the PC junior had 256 kilobytes of ram and .33 megaflops of computing.
nodejs' main binary on my laptop is 44 MiB.
The Apollo Guidance Computer (AGC) we put a man on the Moon with could do 4 kilo instructions per second and 0.43 megaflops and had 2KB of RAM. Apple watch is roughly 900x as fast as the AGC while being being .67 x as large and less than 1% of the weight.
Vs the PC Jr, it's almost 2000x the size of an Apple watch and like 150x heavier.
Isn't it the same thing? CS has other priorities. Answer to the original question is "No, early 80s computers could not have had better software, because today's CS focuses on SaaS income, tracking users and having the tallest Jenga tower of dependencies."