On Fri, Mar 11, 2022 at 9:03 AM Jorge Timón <jtimon@jtimon.cc> wrote:

A major contender to the Speedy Trial design at the time was to mandate eventual forced signalling, championed by luke-jr.  It turns out that, at the time of that proposal, a large amount of hash power simply did not have the firmware required to support signalling.  That activation proposal never got broad consensus, and rightly so, because in retrospect we see that the design might have risked knocking a significant fraction of mining power offline if it had been deployed.  Imagine if the firmware couldn't be quickly updated or imagine if the problem had been hardware related.

Yes, I like this solution too, with a little caveat: an easy mechanism for users to actively oppose a proposal.
Luke alao talked about this.
If users oppose, they should use activation as a trigger to fork out of the network by invalidating the block that produces activation.
The bad scenario here is that miners want to deploy something but users don't want to.
"But that may lead to a fork". Yeah, I know.
I hope imagining a scenario in which developers propose something that most miners accept but some users reject is not taboo.

This topic is not taboo.

There are a couple of ways of opting out of taproot.  Firstly, users can just not use taproot.  Secondly, users can choose to not enforce taproot either by running an older version of Bitcoin Core or otherwise forking the source code.  Thirdly, if some users insist on a chain where taproot is "not activated", they can always softk-fork in their own rule that disallows the version bits that complete the Speedy Trial activation sequence, or alternatively soft-fork in a rule to make spending from (or to) taproot addresses illegal.

Since it's about activation in general and not about taproot specifically, your third point is the one that applies.
Users could have coordinated to have "activation x" never activated in their chains if they simply make a rule that activating a given proposal (with bip8) is forbidden in their chain.
But coordination requires time.

A mechanism of soft-forking against activation exists.  What more do you want? Are we supposed to write the code on behalf of this hypothetical group of users who may or may not exist for them just so that they can have a node that remains stalled on Speedy Trial lockin?  That simply isn't reasonable, but if you think it is, I invite you to create such a fork.
 
Please, try to imagine an example for an activation that you wouldn't like yourself. Imagine it gets proposed and you, as a user, want to resist it.

If I believe I'm in the economic majority then I'll just refuse to upgrade my node, which was option 2. I don't know why you dismissed it.

Not much can prevent a miner cartel from enforcing rules that users don't want other than hard forking a replacement POW.  There is no effective difference between some developers releasing a malicious soft-fork of Bitcoin and the miners releasing a malicious version themselves.  And when the miner cartel forms, they aren't necessarily going to be polite enough to give a transparent signal of their new rules.  However, without the economic majority enforcing their set of rules, the cartel continuously risks falling apart from the temptation of transaction fees of the censored transactions.

On the other hand, If I find out I'm in the economic minority then I have little choice but to either accept the existence of the new rules or sell my Bitcoin.  Look, you cannot have the perfect system of money all by your lonesome self.  Money doesn't have economic value if no one else wants to trade you for it.  Just ask that poor user who YOLO'd his own taproot activation in advance all by themselves.  I'm sure they think they've got just the perfect money system, with taproot early and everything.  But now their node is stuck at block 692261 and hasn't made progress since.  No doubt they are hunkered down for the long term, absolutely committed to their fork and just waiting for the rest of the world to come around to how much better their version of Bitcoin is than the rest of us.

Even though you've dismissed it, one of the considerations of taproot was that it is opt-in for users to use the functionality.  Future soft-forks ought to have the same considerations to the extent possible.