Obviously, the Bitcoin rating below the B range carries more than just the lack of prompt upgrades (as you note in your assessment) but you bring up a good point: the Bitcoin developers are actively and passionately working to improve the network and coin utility. Additionally, Bitcoin might carry less risk than Ethereum or EOS due to mass adoption and recognition.

But does this earn it a "B" range status? I think not because the lightning network, by definition, is deviating significantly from the fundamentals of Bitcoin!

Thanks for sharing, and I look forward to more insight because the almost $500 annual membership is pretty steep!