The U.S. in general only adopts ITU telephony recommendations to the extent that they're needed to interface with other countries. We will never change our signalling or our dialing plan to agree with the ITU. (After all, ours predate the ITU's, and they decided to do something else.)
US pay phones are indeed unlike payphones most other places. They vary enormously, both depending on the pay phone provider and the long distance service. In cities with large immigrant populations it's sometimes possible to find pay phones which offer reasonable international rates, typically 10 cpm, but most pay phones don't offer international coin calls at all. The U.S. is a large country, and most Americans have still never made an international phone call.
For the minority who do make international calls, prepaid phone cards with reasonable rates are widely available, with access via domestic toll-free numbers. VoIP carriers usually offer cheap long distance as well; my Lingo VoIP service includes all of western Europe in the local flat rate (free for the first 500 mins/mo) calling area.
I agree that using a roaming mobile phone in the U.S. is rarely an attractive proposition. We use 850/1900 MHz rather than the 900/1800 used in most other countries, and only about half of our networks are GSM. Even if you do have a quad band phone, the roaming rates are punishing. I have a T-Mobile SIM from the UK which would cost 55p/min to use here, about $1.10/min for all calls, and an Orange Switzerland SIM which would cost CHF 4.50 outbound and 2.80 inbound. Ouch!
R's, John