Question: I am the proud recipient of a brand new, EMV-equipped Visa Debit card through my financial institution -- this card is capable of being used for PIN debit/EFTPOS, signature debit, and ATM transactions, at least in the North American senses of the terms. However, can such a card support EMV chip-and-PIN debit transactions for use overseas in areas where magnetic stripe PIN debit/EFTPOS is no longer supported, or is it limited to chip-and-signature for chip transactions?

Note: [our question about credit cards](https://travel.stackexchange.com/questions/83913) is different because it covers North American EMV *credit* card products -- which do not support PIN debit/EFTPOS or the full panoply of ATM transactions. A Visa signature debit (Check Card) product supports not only signature debit (i.e. credit card like), but PIN debit/EFTPOS and ATM (bank card like) transactions as well. I'm concerned about *all* usage contexts (such as foreign ATMs and automated kiosks that do not have the ability to accept a chip and signature transaction), not just a card-present/manned environment where chip-and-signature fallback is an option, as well.

Answer: 
Because they think more people will pay more to fly to Flagstaff than Cancún. It's as simple as that: airlines set prices to maximize their profit. 

In this case, Cancun is normally thought of as a budget leisure destination. The airline knows from long experience that many vacationers headed to Cancun will simply find another place to go if the flight is too expensive. They believe travelers to Flagstaff will pay more right now. Prices may be seasonal, especially for these destinations, and are based on supply and demand. 

Competition also plays a role. The airline knows who flies between the cities, their prices, and how convenient their connections are, and they'll price accordingly. Multiple carriers competing aggressively on a route will typically drive prices down, while they generally remain high when few alternatives exist. 

And when it comes to Flagstaff, there's no competition. Flagstaff is a small airport served only by one carrier, American Eagle, with a couple of flights a day to nearby Phoenix. The airline pretty much has you over a barrel because you have only a couple of choices: pay whatever they want to go to Flagstaff, fly to Phoenix (or an even further away airport) and make your way to Flagstaff some other way, travel by a less convenient method such as a bus or trains, give up and go someplace else entirely, or give up and don't travel at all. In contrast, you can get to Cancun through connections on several different airlines. American knows this, and will happily use its monopoly over flights to Flagstaff to charge you for the convenience of flying there rather than making you drive from a farther away airport.

But the real answer is that airline ticket prices don't make "sense" in the way you're trying to understand them. They cost as much as the airline thinks the market will bear in a way that maximizes their profit, not on a per-mile basis or other "logical" structure.
It's basically "whatever the market will bear" with some important exceptions. Fare history for the city pair plays a role and helps predict the future. A carrier new to the route may lower the fare to attract business. Flagstaff has relatively few people, and by laws of chance, there will be far fewer people going PIT-FLG than PIT-CUN.  

Also, it costs a carrier quite a lot to touch down anywhere, so those costs must be spread between only a few passengers.
Finally, Flagstaff is at high altitude, with adverse winter weather. Both factors increase operating costs. With far lower fares, some greeters may consider a quick dash down I-17 to PHX (Phoenix) a good alternative.