Let's see a huge international software company do that!

- Engineers generally wouldn't want to do it. Adding layers of indirection between them and the customer would make them happier, but also less effective.

- Optimally, the engineers should be familiar with the software internals. They'd have to specialise in one or two products. If they're actually working on the product at the same time, it's less of a problem. But you're still going to need more CS reps than otherwise.

In a startup, the engineers will have more invested in the product, so they'll be more willing to do it. In any case, there's likely to be nobody else. And there's probably only one or two products, so the CS reps can all be familiar with all (both) of them.

I don't think it would be impossible, just hard. You'd need the CS reps to recognise when a problem is more than just user error, to take a good bug report, and then to be able to get a hold of the right person to get it fixed quickly. Which also requires that it can be fixed quickly; this may be something else that large companies have problems with.

(edit for formatting)