L2bravo, there are a couple of reasons why Spyderco can't match companies like Strider, Hinderer, or CRK in terms of rebuilding or 'Spa Treatments' as some people call them.
First there is the issue of scale. Spyderco makes more knife models than all three of the these other brands combined. If you look at all the models and major variants they have made in the last few years, you would need a warehouse just for spare parts.
The other issue is that Spyderco follows a a manufacturing model that incorporates running changes to their knives as they either identify a problem with a model or find a slightly better way of doing it. I believe the term is something like CQA (Continuous Quality Assurance). So even if you have the exact same model THIS year as the one from LAST year, the parts from one knife might not fit the other.
On the other hand, within their scope of work, they can and do quite a bit. They can sharpen the knife back to a factory edge, regrind the blade if the tip gets broken, replace screws that might have fallen out, and in some cases even retune the knife to get proper blade centering.
If the problem is a true warranty issue and they can't fix it, they will issue you a credit towards another Spyderco knife.
All in all, I think that they do an awesome job considering the mass different models they have produced.