Maybe if the board had information that hadn't been published yet showing that the company's financials had completely tanked since the last earnings report it would be different, but other than that, Twitter's financials are obviously public, and even if the board used something like the DCF method and obtained a number much lower than the market cap, that has absolutely no bearing on whether they would accept a certain price from Musk.
So, no, it's really the share price that matters in this situation.
Also, even if you're purely talking about valuations, there are other common valuation methods like the comparable method that look at what similar companies have received based on their share price, so the idea that the board would decide to sell purely based on cashflow projections is not correct.
> Maybe if the board had information that hadn't been published yet [...]
Part of my analysis is based on the rumor that Twitter completed a valuation over the weekend, and it wasn't super favorable. But I've got no reliable reporting that establishes that.
Either way, my real point is just that the board could easily have stopped this deal if they wanted to; in fact, they didn't even have to do anything to do stop it.