Sure, the gross margins are healthy for many SaaS companies.
Take a look at the other expenses. They eat that margin, and then some, quarter after quarter, year after year.
Where does it end? Will these companies ever be profitable? I'm invested in several public SaaS companies, just following the trend...
I had to look it up, but Twilio gross margins are healthy -- 55%. AWS expenses are not really a problem for a company like Twilio, their well publicized arrangement of relying on other large tech companies is a bigger threat.