The reasoning for the delay on Insider rings (as far as I know, may be wrong) is because the Production devices get updates (including firmware and OS) direct from HP, while Insider devices get it from Microsoft (not HP). So for firmware to show up on Insider devices it has to be separately published by Microsoft, while Production gets it as soon as HP releases it.
Again, not 100% sure about this, but I'm pretty sure this is the reasoning for the delay. Ideally MS and HP can work together to get the updates out to everyone faster, but until then, it's just one of the downsides with using prerelease builds.