Respeccing is a reasonably common thing to see in games but it's usually not as exploitable as it is in 7DtD. Like, if I change from a fire wizard to an axe berserker in some RPG or I drop some useless skills to swap in useful ones I'm not really exploiting anything other than that maybe one class is stronger early on then falls off later or whatever. In 7DtD speccing heavily into vehicles is meant to have the opportunity cost that you give up combat effectiveness, but if you just build everything and then swap in some combat skills then you get to have your cake and eat it too.
At least the Fergettin' elixir is pretty pricey, though someone already specced into Intelligence can somewhat circumvent that too due to Better Barter.
Anyway, this 'issue' should be addressed by a21's release since recipes will no longer be something you can magically learn by killing zombies.