Something feels off about that and the other time lines. I’m sure I remember paying for Airtable pretty soon after it launched for a couple of months. Perhaps the timeline chart is literally just for the B2B channel?

I don't think the data is very "scientific", e.g: slack was officially launched in 2014 and got immediate traction. Yes there were 4 years of development but it wasn't even the product they wanted to sell.

If it takes a year or more to go from launch to first paying customer, what are you doing during that time?

Of course, you could be purposefully giving your product away while building the premium, paid-for features. I think that applies to some of these companies, and I'd be more curious about the time from launching that version to paid customers.