I think the metaphor still works. A lack of hammer implies only having a screwdriver. The point is you should have a tool box (and garage and workshop and spa

I think the metaphor still works. A lack of hammer implies only having a screwdriver. The point is you should have a tool box (and garage and workshop and spare bedroom) full of tools so you have the exact tool you actually need. What the Phillips head and pozidrive represent in this metaphor are left as an exercise for the reader. As is the adjustable spanner.