ok,
dread you have also right since visa versa the mt,low kick guys could not be so successful in fc bouts in general terms ...I remember the fight of hoost vs roufus in fc...roufus was playing in the ring, hoost had hard times and was making some little faults(like low kicks) which was counted...of course, a fighter like hoost was not easy even for roufus...it is not an easy concept for leg kickers (mt or kb/low kicks) to prevent their self kicking and leg block abilities...hence, they need at least 3-4 month prior for preperation for fc ,but even under those circumstance it is again not sufficient for success...
common general tendency:

-mt people can be successful "in oriental and western kb types with low kicks" if prepared enough ...(like kaman,carbin,çolak,yamali,royers did in the past and still many newcomers do...)visa versa they have much trouble in fc bouts like royers,kaman,hoost did in the past...

-fc people cannot so easy be successful in low kick bouts ...roufus, dennis,jackson were kings in their cathegories,but in other styles in vain...(by the way, urquidez's situation was different since he had chosen low kick bout and prepared good enough...

this is a very deep subject and there are many parameters why so and why not so...but you have right ...the fighters who can be successful in different disciplines need to have much respect than the single one havers...(like fred royers,kaman,carbin did in "fc,mt,kb-lowkicks and savate"...believe me ,it is not so easy concept to be successful in those sections all together...)