Excrab you would have to fly something newer to understand how really primitive the 737 is. A friend described it as an ergonomic slum 33 years ago, and it hasn’t improved much. The overhead panel is a 60’s throwback, the instrument panel mid 80’s.
The basic fuselage is a 50’s design with 50’s doors and escape slides (NOT slide rafts). The cabin, galleys and toilets are all cramped as is the flight deck. It's too low, baggage has to be loaded by hand instead of containerised. It is loud. Really loud.
The 737 is a tarted up 60’s plane built with 50’s know-how and design thinking. Someone compared old to new cars. You can still drive around in a ‘63 Impala but I wouldn’t let my kids drive one. Same thing applies here.
I have flown aeroplanes made in the 30’s, 40’s and 50’s. All good in their day, but their day has passed.