A lot of people find it very, very difficult to get started from a blank slate. Automated onboarding/email sequences/video tutorials/etc gets you to a point, but it still leaves guesswork in the process and (candidly) one can always blow off a computer but blowing off a person who has been talking to you for weeks is socially harder to do.
This also allows you to do basically a hybridized product/consulting model, since if (without loss of generality) Jason Fried is spending 2 hours for you talking about your business' challenges as he gets you up to speed on KYC, that's essentially equivalent from the customer's perspective to "Rent Jason's brains", but (crucially) the majority of the economic activity actually comes from the product whose use is enabled by the mini-consult rather than through consulting itself. This lets it scale to the moon. (Also, as every consulting company at scale will tell you, you can have Jason Fried's insights on your company actually delivered by an understudy. 37signals certainly doesn't lack for smart people who understand the 37signals playbook.)
This is currently giving me fits, since I haven't figured out a great way to deliver it consistently for non-enterprise accounts given that I'm 14 time zones away from many customers, but it's one of the big things I'm working on currently. The word on the B2B SaaS grapevine is it works very, very, very well at moving $X,000 to $X0,000 per year SaaS accounts.
I'll blog about this if I ever manage to systemize it successfully. (As usual, the plan is 1) Throw stuff at the wall and figure out what works. 2) Write down what worked and execute against that plan. 3) Pay someone to do #2. I'm currently somewhere in stage #1.)