It's because you have not looked hard enough. There are plenty of great musicians out there, you jut wont find them by listening to the radio or from TV and Movies. Theres some great musicians HERE...
Anyway, mini rant over.

Most modern commercial songs are mixed for tiny in ear headphones. Boosted bass etc... The mobile phone being more prominent than a HiFi. Old songs where made for wooden cabinets.

New rant begins:
In the past, when you committed a song to a recording it was a one take, and thats it. No retakes, no can we try this. Songs were rehearsed and arranged and perfected long before the huge cost of capturing it. The limited dynamics of the mediums also meant arrangements were thoughtful, not just everything from beginning to end. Leaving space in the mix was done pre record. Then tape came along and if you messed up you could try again for a limited number of times. It also required engineers - scientists. They built the things you recorded on. They knew how to get the best.
Today a person off the street can do all the jobs with the device in their pockets. And thanks to XFactor, most average musicians think they are great.

TLDR : I blame mobile phones and society.

 

Yes - that's ONE important dimension of the problem imho.
Nowadays we have an artistic and content problem - maybe very similar in classical and in light music too.
I'm an opera singer and feel very often a lack of feelings, message, content and passion in our music on stage and in recordings.
Why I'm singing...and what?? THAT'S an important question.
We have technical perfection, HiRes, and all looks great. But often a great emptiness...inside.

If I have to tell something personally to my audience I'm (hopefully) able to touch, move and reach the people.
This builds a bridge for feelings and thoughts - a real connection between people right in the present moment, face to face.
To tell something right from my heart - THAT'S the reason for making music - in the past, present and future.
AI will produce some entertainment, maybe.
But real art is something different.

The technical dimension of the problem is only following these developments - in analogue times the technical staff and devices were only a support for the music and the performing artist . Nowadays the technical staff DOES the music by devices and sometimes unfortunately they need support by an artist/singer.
Machines produce melody and rythm - but doesn't have a heart...and therefore no feeling and message.

A song has to be a story. You have to tell this story with all the powwers at your disposal.
More ART and heart, less attention for technical devices.
Technology has to be a support, not an end in itself.

 

Why analogue technology is more useful for making good music?
Maybe because analogue devices are only able to support the musicians technically, while digital technology reduces the human artistic part of the process of music making drastically.

The content of the videos above was very interesting for me - Thanks!

 

I'm thinking track count being limited was partial reason. No stacking 20 tracks of the same rhythm guitar part type sludge like nowadays for example, heh.

 

They worked around track limitations all the time. They could do pretty much everything we can in the DAW today to get whatever stacking results they wanted. Groups, buses, submixes, even as far as using an entire additional console mixer for all the mics used to record just the drum kit. Many, or most, of the two inch tape machines could record 16-24 tracks simultaneously; depending on the year and manufacturer.

Most people had no imagination of all this technology we have now. It's like not realizing how slow your computer really is, until you buy a new one. Making a record with lots of channels' content was possible and done all the time. Everything was a laborious process, but that was just how it was done. Anyway, they could do whatever they wanted up to their threshold of pain and suffering.

These are all factors in how they ended up with "that sound" that the thread is about. I think the lack of quantization is a big one. Instead of someone wanting all the timing perfect, to make editing in a DAW easier; the band played along with a live drummer instead of the drums being recorded first, while playing to a click track. Musicians adjust to one another when jamming together. Playing in time to another source which is already laid down with static, non-adjustable timing is not easy for everyone. Many drummers had serious trouble learning how to play to a click track when it first started turning into a standard workflow; but someone would say their playing live without one was tight timing.

I think if we really want one scapegoat for the entire thing, it is the emergence of the click track.