Don't forget they ALSO have Orlando at 14M+, so that's 28 million people for Miami and Orlando together, in that scenario the two metros certainly touch each other, and Orlando and Tampa have also merged (Tampa would have what, another 10M?) ...
All I have to say to the people who wrote this article, is to offer them my Chicago projections:
(yep, I dug them up

)
1840 - 4,470 (actual)
1850 - 29,963 (actual)
1860 - 200,846 (projected)
1870 - 1,346,297 (projected)
1880 - 9,024,406 (projected)
1890 - 60,491,785 (projected)
1900 - 405,484,419 (projected)
1910 - 2,718,015,581 (projected)
1920 - 18,219,217,187 (projected)
1930 - 122,125,817,578 (projected)
1940 - 818,625,474,740 (projected)
1950 - 5,487,354,600,000 (projected)
1960 - 36,782,462,000,000 (projected)
1970 - 246,557,700,000,000 (projected)
1980 - 1,652,708,800,000,000 (projected)
1990 - 11,078,325,000,000,000 (projected)
2000 - 74,259,475,000,000,000 (projected)
2010 - 497,771,060,000,000,000 (projected)
2020 - 3,336,625,100,000,000,000 (projected)
2030 - 22,365,838,000,000,000,000 (projected)