I'll put it out there that I think we see an NBA team in Montreal (
#12 media market size for US/CAN, roughly equivalent to Tampa and Seattle) before we see one in Mexico City. I think the reason Silver brings up Mexico City is to publicly emphasize the breadth of strategic thinking that the league has, the breadth of their vision and how open-minded they're being. I don't think they'll actually pull the trigger on that, not while they've got Tampa, Seattle, St Louis, Pittsburgh, Baltimore, Raleigh, San Diego, Kansas City, Columbus, Cincinnati, Las Vegas, Austin and Jacksonville all on the board. And Vancouver is roughly the size of those last two.
On the other hand, starting a Latin American-wide basketball league and going head to head with FIBA there - given that they now have the money to light anything FIBA does on fire and piss on the ashes - might be something they'd actually try. Africa is easier for the lack of existing competitions / infrastructure, and Europe is FIBA's home turf with a lot more history and political complexity to the league and competition structure. But South America is an option where there's not going to be any sort of deference to FIBA and they could actually compete.
Imagine a separate, NBA-funded and operated Latin American league with teams and local ownership in (metro population):
1. Mexico City, MEX (21.8M)
2. Sao Paulo, BRA (21.1M)
3. Buenos Aires, ARG (13.7M)
4. Rio de Janeiro, BRA (12.3M)
5. Lima, PER (9.9M)
6. Bogota, COL (9.3M)
7. Santiago, CHI (6.7M)
8. Belo Horizonte, BRA (5.8M - or pick any of a half dozen other Brazilian cities)
9. Monterrey, MEX (5.4M)
10. Caracas, VEN (5.3M)
11. Guadajalara, MEX (5.3M)
12. Guayaquil, ECU (3.0M - probably not Quito since that's at 9500' elevation)
13. Guatemala City, GUA (3.0M)
Take your pick for #s 14-16: Panama City (1.9M), San Jose Costa Rica (1.4M), Puebla MEX (3.2M), Toluca MEX (2.4M), Cali COL (2.9M), a fourth Brazilian one (Porto Alegre 4.3M, Brasilia 4.2M, Fortaleza 4.0M, Salvador 4.0M), etc. All would be multiples bigger than Milwaukee (1.9M metro population), OKC (1.4M), New Orleans (1.2M) or Memphis (1.3M), so even if there's a large gulf in disposable income per capita, there's enough upper middle class people to fill the stadium and plenty of fans to watch / buy merch, and you'd be betting on economic development and growth in fandom to eventually make it a worthwhile proposition.
And if the NBA controls the league, then they can schedule competition against the NBA itself, and/or the G League, or other international competition. It can be another place to stash talent for development and/or find new talent (players, or refs, or coaches).
A nonstop flight from Sao Paulo to Mexico City is 9.5 hours, so that might present a problem (keeping it within South America only, Buenos Aires to Caracas is 7 hours flat). And operating businesses in that part of the world has complexities that Americans don't usually contend with, etc etc. But if I'm the NBA I'm thinking roughly this big at this point. What can they invest in, basketball-related, to keep growing using all that extra money coming in the door? How can they grow goodwill and global interest in their league? This was the single greatest aspect of David Stern's vision and tenure - seeing well before anybody else, as early as 1985, what the league could become internationally. If he were still around, I bet this is what he'd be thinking about.