Cheaper manufacturing costs with the added “benefit” of making it hard to repair so users buy another one if it breaks

Short answer: late stage capitalism

Long answer: Because they don’t have enough money to make rent on time and the associated fees are less than the late fees. Being poor is expensive.

Age is the big factor. It does two things:

1. Eggs gradually lose water, which introduces more air into the air cell and between the membrane and the shell, making it all a bit looser as you peel.
2. The pH increases, reducing the attraction/attachment of the boiled egg white to the membrane, which is why fresh egg shells are more likely to tear strips of white off as you peel.

Eggs in the US can be up to 60 days old at the time of packaging, then are considered good for another 45 days. Large flats of eggs can contain eggs from multiple batches of varying age, so some eggs might be two weeks old and others two or more months.