Yeah, honestly I'd think it were sad if they were, say, manufacturing employees who were laid off and had poor prospects, but in today's market any decent engineer or product person who worked at Twitter would be snapped up in a second.
> I'm going to assume that yes -- their business model was based on annual revenue.
Then you'd assume wrong. The goal of the board is to maximize return for investors. In WhatsApp case, it's not hard to see that their goal was to grow as fast as possible, revenue be damned, so they could be a very attractive takeover target for a company like Facebook who could eventually hope to monetize that user base.