The US started using mailboxes 14 years after the UK

In 1849, the Royal Mail first encouraged people to install letterboxes to facilitate the delivery of mail. Before then, letterboxes of a similar design had been installed in the doors and walls of post offices for people to drop off outgoing mail.

In 1863, with the creation of Free City Delivery, the US Post Office Department began delivering mail to home addresses.

Putting Ctrl in the home row by replacing the useless Caps-Lock is sufficient for me .

Alt is easily reached with the thumbs and shift is already close enough to the home row, with shift-ctrl using both pinkies.