One thing that confuses me about the scaling debate happening in Bitcoin right now is that a significant number of people apparently want to leave SegWit on the table in spite of the huge benefits it offers that are unrelated to scaling.

SegWit is the most well-tested way to alleviate transaction malleability and quadratic sighashing attacks. It creates an avenue for easy improvement of Bitcoin’s scripting language, which will allow for more advanced smart contract features. It opens the door to an exciting world of protocol interaction with Lightning and other networks. Scaling, or increasing transaction throughput of the network, can be thought of as completely peripheral to the benefits of SegWit.

As a fairly impartial observer without much skin in the game (aside from a few Bitcoins and small Core contributions), SegWit looks to me like the obvious way to move the protocol forward, regardless of the blocksize angle.

In fact, if I were, e.g., a Bitcoin Unlimited supporter, I’d be inclined to get SegWit activated and then try for a hardfork. After all, benefiting from Core’s work and activating/adopting SegWit doesn’t mean that you necessarily submit to their continued reign over the protocol in the future. Why not selfishly reap the benefits and then take a crack at pursuing a fork?

To leave SegWit on the table seems fairly irrational to me – it feels like too big an oversight. And I don’t think anyone who has a technical horse in this race is dumb enough to miss its obvious benefits, which creates interesting circumstantial evidence in the case of ASICBOOST.

If we agree that SegWit has significant benefits unrelated to scaling, and its adoption doesn’t necessarily lock anyone into the Core implementation going forward, the question remains: why fight SegWit?

The recent revelations re: ASICBOOST provide a convincing (if not proven) narrative on why people who are rational, intelligent, and savvy with the protocol would be ignoring (and in certain cases antagonizing) an otherwise net-positive change. Unless I’m missing some technical aspect which would explain how SegWit activation locks in Core dominance, it doesn’t make sense that a significant plurality of a community invested in Bitcoin’s success wouldn’t be for a SegWit activation.

I can completely understand arguing over the next steps and I can understand the desire for increased transaction throughput, but SegWit itself seems like a given.

The most plausible explanation for me is that there is a vested interest in not changing block header contents due to ASICBOOST (and undiscovered ilk), and that interest has trickled down from powerful mining incumbents to well-intended but unaware technical participants.

The last few paragraphs are pretty heavy speculation (and I’m happy to be corrected), but I’m unable to see a more convincing explanation.