Not exactly one sentance but basically... after the Cuban revolution all the previously independent cigar brands like Montecristo, H Upman e.t.c. were all forced into a single company called Habanos SA. That company controls all Cuban cigar production, every year they bring out limited edition releases of cigars which are released sometimes in very ornate packaging and typically in very limited quantities these have basically in the past 5 or so years become "investment grade" cigars.

In addition to that, said company, Habanos SA grants regional monopolies to specific companies to distribute their cigars, these companies bring out "Regional Special Editions", which are special edition cigars available for sale only in the country they distribute too. Again the tendency has been towards limited quantities and much higher prices in certain countries.

They've basically become a bit like Modern art or old single malt scotch, they're so expensive that even if you can afford to buy them you think twice about smoking them because you know that next year they'll be worth even more. That and collecting turns into as much of a hobby as smoking them does.

Because people value collecting them more than they do smoking them. Would you smoke your 5 million dollar cigar collection? Probably not. It's burning money!