Over 15,000 users paying $30 per month. $260 million valuation. Perfectly scalable. If you'd like to learn why you're wrong, I encourage you read one of the many lengthy, sincere, and detailed articles with the founder of Superhuman, starting with this one. https://www.drift.com/blog/how-to-measure-product-market-fit...
And did you update your email signature in the way the OP suggested? Specifically, do you let everyone getting email from you know that you not only track that read it, but when they read it, and even where they were when reading it?
I ask, because that would be the ethical way to handle what this app is doing for you.
That's extremely high for an email client that only runs on a single OS, but if that's true, that's 450k/month or 5.4M/year. How do you get to 260M valuation?
When you say it's "perfectly scalable", what are you using as your reference? That is, what other SaaS has $30/month pricing, especially one in a field as crowded as email and work messaging (i.e. Slack). Obviously, SH is far from having, or needing to have, a finished business plan, and it seems likely that the $30/user won't be the default offering or main breadwinner. But that raises the question of why that number is relevant in the first place when assessing SH's viability.
Well, I pay $5/mo for SaneBox as I always forget to unsubscribe and delete it's pathetic labels. Many of us pay for useless stuff. But some point, we stop, and then the company tanks.