Well it should have some free play and an inch is good
If there is a lot of slop in the linkage, You can't press it down far enough.
Lets say total travel of the pedal is 6". It's at the end of a 10" lever arm. So the hole for the linkage arm only travels 2" for 6" of pedal travel.
3 to 1 ratio in this example.
The 1" of free play is really 1/3 of an inch. out of the 2"
now if both the rod and bell cranks are warn, say it add's up to 1" of slop total. that's 3" on the pedal before anything starts to move. So were you previously had 5" of travel to move the clutch arm, you only have 2". That aint going to move the arm much.
here is an example of a worn bell crank:
You can see were it adds up....