Twilio Raises A $70M Series D As They Consider An IPO
techcrunch.com
techcrunch.com
On the web, there are no longer barriers to entry.
If I'm an enterprise, I'll go with Twilio over some 2 week old startup because of its proven track record and the likelihood of being around in a year.
I hate to use this example because its a bit cliche but Google entered late into a field of established players and won. Microsoft beat IBM (this one applies only to the PC, I know IBM is still a force to be reckoned with). Stripe, Balanced, and Square are able to compete with PayPal for accepting payments. I know these arent all enterprise-specific but I didn't take the parent's comment to be about enterprise only.
What you'd do as an enterprise and what real enterprises would do are two different things.