My old phones with removable batteries fit in my pocket just fine.
https://www.apple.com/iphone-13-pro/specs/
Also the new iphones are waterproof, your old phone was not.
There are ways to protect devices from water without making the whole things unserviceable.
What exactly is your complaint? That they are not as easy to service as your old flip phone? The modern iPhone has more computational power and technology packed into it than a full size desktop computer from 3 years ago. Modern phones are so much more than just a phone and will never be as easy to service as your old flip phone. No tech company will ever satisfy your complaint if that is what you truly desire.
As for waterproofing I have never in my entire life ruined a phone by dropping it into water. I would still prefer removable batteries. It is a good trade-off in my opinion.
I am willing to concede that my opinions might not reflect those of the general public.