It's quite clear that you can go pretty far in a sport setting with a small set of high percentage techniques.
When you get into street and weapons, it get's a lil murky. But, personally, I believe the same methodology applies. Not to say there are catch all techniques for all weapons, but individually this applies. Like a set for knife defence, staff, stick, sidearm etc etc...
It really comes down to your goals and priorities. If street defence is your goal, you are best served to be a jack of all trades. To be at least functional in all likely scenarios.
"Jack of all trades master of none, often better than a master of one." is the real quote that is, more often than not, taken out of context and used incorrectly.