Because the name of the game is Improvisation, Improvisation, Improvisation.

In a perfect world one would have a walk in tool shop that one could carry around in one's wallet.

Sadly, this is the real world. A multi-tool is like a Swiss Army Knife. Won't do any job brilliantly, but will do them just well enough. On a decent tool you get a pair of pliers, A few screw drivers. One or more mediocre to fair blades. A file(diamond coated for choice. A pretty good saw plus one or two other bits.

Think of a tool as being a force multiplyer.