Writing drivers is easy, getting vendors to write *correct* drivers is difficult. At work right now we are working with a Chinese OEM with a custom Wifi board with a chipset with firmware and drivers supplied by the vendor. It's actually not a new wifi chipset, they've used it in other products for years without issues. In conditions that are difficult to reproduce sometimes the chipset gets "stuck" and basically stops responding or doing any wifi things. This appears to be a firmware problem because unloading and reloading the kernel module doesn't fix the issue. We've supplied loads of pcap dumps to the vendor, but they're kind of useless to the vendor because (a) pcap can only capture what the kernel sees, not what the wifi chipset sees, (b) it's infeasible for the wifi chipset to log all its internal state and whatnot, and (c) even if this was all possible trying to debug the driver just from looking at gigabytes of low level protocol dumps would be impossible.
Realistically for the OEM to debug the issue they're going to need a way to reliably repro which we don't have for them, so we're kind of stuck.
This type of problem generalizes to the development of drivers and firmware for many complex pieces of modern hardware.