Leaving Shawn's statement aside for the moment, let's look at the numbers.
Mongoose has 47 skills or skill groups in the career tables, 18 of which split out to 68 options, or roughly 97 skills total. Those 68 leave rank zero echoes within their groups, so they aren't as exclusive as the other 29 which leave no echoes in other skills.
CT81 plus Supplement 4 and Books 4-7 yields a more complicated picture, with singular equivalences scattered throughout the list, no zero level echoes, and a host of later skills that group the earlier skills together.
Book 1 has 30 skills listed, but states that Gun Combat and Blade Combat must be assigned to specific weapons, of which Book 1 lists 21. Book 4 adds another 11 skills and redefines Gun Combat to use seven categories; it also uses a Book 1 definition for Heavy Weapons, with a skill representing individual weapon systems. Book 5 adds several more skills. Book 6 adds five more and redefines several of the cascades. Book 7 adds two more and redefines cascades again. Supplement 4 adds one more plus the bow weapons.
Looked at this way, the two systems have about the same sized base skill sets, but treat the specialties differently. CT sends you out along a specialty branch with blinders on, while Mongoose spreads zero level echoes over a skill group that you pick one specialty in. PCs gain access to more of the skills in Mongoose, on average, if only at zero.
And, I'll note, at least some of the service breakdowns of Gun Combat in CT do have SMG as a separate choice.
