Very small pointy things are the Achilles heel of any tire that uses a fabric-based puncture protection scheme (Kevlar, PolyX, Vectran, etc.). These high tech fabrics have amazing properties in terms of strength and flexibility and they're so tight you tend not to think of them as fabrics, but the reality is that they are designed to catch things rather than block them. This usually works well for things like glass and sharp bits of rock which have some width to their edges, but something with a very fine point can slip through the net. Some tires like the GP 4 Seasons have multiple fabric layers, which reduces the chances of a point getting through a bit, especially if the point can break off, but it can still happen.

Of course, the alternative is something like the thick strip of rubber that the Marathon Plus uses. That's great for stopping pointy things, but the downside is that they aren't nearly as light or flexible and you feel that (the lack of flexibility at least) in their rolling resistance.

The other problem with the tiny bits of wire is that they can stick in your tire and you might carry them around for weeks without knowing it while they work their way through your puncture protection belt. Again, having rubber thicker than the wire is long is the best protection, but I'd rather live with a flat now and then. I guess this depends on your local conditions, but to me it's like asking if I'd want tires that would stop that nail. I average around 4-5 flats a year, and most of those are with tires that are hitting their mileage limit and wearing out. I'm not going to use thick, heavy tires for 4000 miles a year just to avoid 4-5 flats.