Their whole philosophy is that you don't need to scale or sell out for VC money, and everything they did (and didn't do), is consistent with that.
Hey is just another service, like Basecamp, for those that want to pay for it, to sustain a profitable business. Not some Gmail-level wanabee.
I also happen to agree with that philosophy, considering eyeballs/VC/exit-oriented companies that aim for world domination poison and detrimental to consumers, to society, and to software.
I'd also like to note that what you call "boutique" is what, for the most part of capitalism, and even in IT up to the late 90s, we used to call a regular business.
Suddenly running a business with 10M-100M of revenue and a hefty profit is somehow an insult, and it's "boutique" or "lifestyle"...