No, that's totally wrong.
US (NPD numbers, from a time when the NPD was not entirely reliable):
http://www.neogaf.com/forum/showthread.php?p=130137491#post130137491
Also (from later in that thread)
http://www.neogaf.com/forum/showpost.php?p=130207634&postcount=64
The key here is the claim of 1.45 million shipped to the US. I thought it was higher, myself -- the SCD and its games seem more, not less, common than the Saturn here, and the Saturn sold 2 million in the US -- but it's believable, I guess.
Japan:
http://segaretro.org/Sega_Mega-CD#Japan says 100,000 sales in the first year of release, that is late '91 to late '92. The system pretty much died in Japan after the end of '94, with VERY few releases in 1995.
http://ja.wikipedia.org/wiki/メガCD Japanese Wikipedia says 380,000 Mega CD systems sold in Japan overall. I don't know if that source is reliable or not, though;
http://ja.wikipedia.org/wiki/メガCD#cite_note-2 Isn't that a European magazine? The number does sound accurate however. 380,000 is 11% of the Genesis/MD's Japanese sales total, a pretty good attach rate for an addon. The Turbo CD did do better in Japan, but even that didn't sell to a majority of the base PC Engine's ownership base.
Europe:
Unknown, except that only 60,000 Sega CDs had sold in the UK as of August 1993, if citation #11 is accurate:
http://en.wikipedia.org/wiki/Sega_CD#Launch Considering that in the UK sales weren't great, and that the Genesis sold 7-8 million systems or so in Europe, I have trouble imagining that more than a few hundred thousand SCDs could have sold in Europe by the end of its life in early '96.
Corroborating that, Sega-Retro says:
4% of ~7.5 million is 300,000.
You add these numbers up and you get 2.13 million systems sold. Add to that the unknown but surely low Australian (unless they were included in Europe?) and Brazilian numbers to get a total that's probably only slightly higher than that 2.13 million number. If I under-estimated European Genesis sales (and thus also EU SCD sales as well), then add a little bit for that. But those numbers are probably small, so even 2.5 million total sold is perhaps an overly-optimistic guess. I wish it was higher, but these numbers are all very plausible.
That 2.7 million number may or may not come from there, but that it sold 2 point something million systems doesn't.
They were many of the most popular games, though. It's easy to find the FMV games in large numbers, but the better, non-FMV stuff is often much less common!