Most of the large marketing ecommerce/enterprise market was captured via ExactTarget/Salesforce, Oracle/Responsys/Eloqua, IBM/SilverPop/Acoustic, Adobe/Neolane/Marketo by the mid 2010's.
SendGrid/Twilio was another a few years later, Amazon SES is ok, then you have some of the smaller market players (MailChimp, Constant Contact, etc).
Hard to scale/grow a startup in any real way when there are so many fairly well entrenched solutions across industries and company sizes.
Most of the large marketing ecommerce/enterprise market was captured via ExactTarget/Salesforce, Oracle/Responsys/Eloqua, IBM/SilverPop/Acoustic, Adobe/Neolane/Marketo by the mid 2010's.
SendGrid/Twilio was another a few years later, Amazon SES is ok, then you have some of the smaller market players (MailChimp, Constant Contact, etc).
Hard to scale/grow a startup in any real way when there are so many fairly well entrenched solutions across industries and company sizes.