Car/Automobile Servicability: Why so difficult?

Hi,

I understand that modern cars have features like complex computer programs and such, but, in the "old days" when cars were more electro-mechanical instead of computer based, practically any auto mechanic in even a small out of the way or very rural gas station and/or auto body shop could pretty much repair and even rebuild the car or truck from the ground up. Even a lot of everyday home mechanics could do minor and major repairs in their home garage. Nowadays, however, this has changed. There are repairs and reconstructions that require expensive (hundreds to thousands of dollars) and specialist computers and equipment. It doesn't seem fair. Also, with all the new rules and regulations, if a car guy wanted to drive around a 1950s style car, say a Cadillac or an old Chevrolet or old time Ford, built with all the exact features as it had back then, he would face all sorts of problems due to new rules and regulations. Why is this and what can be done about it?Example: On one modern car, in order to replace a broken headlight, instead of being able to go down to an auto parts or junk yard and getting a replacement light, removing the old one, and screwing in the new one, the person has to bring the car into one of the established repair shops for that car, and replace the entire front end or something. That's not right. Thoughts?

Please help.

I didn't find the right solution from the Internet.

References:-
https://www.spyderco.com/forumII/viewtopic.php?t=69549
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Thanks!

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