I can speak fairly knowledgeably as I headed up all of Voxeo's developer community and support in the early part of this decade (and as employee #1 and co-founder Voxeo). In a pre-social media world, marketing involved a lot of face-to-face contact, primarily at conferences for developers: Cold Fusion, PHP, ASP etc. We held app contests, live coding demos making people's phones ring, sponsored meetups and conference after parties. (sound familiar?) We were out there...just apparently not at the same ones you were at (sorry).
>> Show me pricing lists and contracts from 10 years ago indicating it was cheap as Twilio was 2 years ago.
I honestly don't think any exist...not because they were lost, but because we never charged anything back then..nor have we ever charged developers. For production apps, there's no doubt that the cost of transporting data has dropped dramatically in the past 10 years. What we can do for pennies now, cost dimes 10 years ago. Of course, we also had to walk 10 miles to school, in the snow, uphill, both ways ;-)
>> But it's the focus on getting the basic fundamentals as easy for people to use as possible which has created the Twilio loyalty and fandom they have relative to voxeo/tropo.
You are absolutely correct. There are some things about Tropo that are still overly complex. We're working on that. Fortunately it's easier to simplify features than to add new ones.
>> Twilio has (imo) about a year to add some more features that people are asking for before people jump ship.
I'd tend to agree. By my estimation (based on how long it took them to burn through their first round of financing) That should be right about the same time their latest round of funding runs out. No time for resting on laurels. :-)