Q: What does Mailchimp do that Hubspot cannot?
Short A: You're comparing 'apples' to 'orange'. (literally)
Ok. First of all ...
MailChimp is a newsletter email service provider (ESP) turned ESP turned pseudo marketing platform turned pseudo ecommerce marketing platform with absolutely zero CRM capability.
Like Batman, MailChimp has a great 'costume' -- their excellent marketing as a do-it-yourself (DIY) email automation platform AND their newly updated drag-n-drop email designer. Also, like Batman, MailChimp has cool tools -- multiple lists, groups, and segments.
However, HubSpot is some 'other world isht' -- a fully mature marketing automation platform currently evolving into a fully integrated ecommerce marketing platform which also includes a native CRM with soon-to-be-functional conversational marketing capability. (cite: Shopify native integration and Motion.ai chatbot functionality announced at INBOUND17)
Like Superman, HubSpot has a great 'costume' -- their prolific inbound content marketing machine. Also, like Superman, HubSpot has cooler tools -- native smart lists which are auto-updated based on criteria you set giving you 'x-ray vision' into your CRM, and workflows which allow you to basically 'program' the automation around nearly anything you can dream of (within reason) -- sorta like making the Earth spin faster to travel through time.
When stripped of their costumes, MailChimp (like Batman) is absolutely no match for HubSpot.
In fact, it's not even a fair comparison. We're talking humans compared to aliens who gain superhuman strength simply being in the presence of a yellow Sun -- aka: HubSpotters! haha
Make two lists ...
-- one for awesome email service providers trying to become marketing automation platforms (with zero CRM capability).
-- one for fully mature marketing automation platforms with native CRM capability and super human strength built-in.
Then decide which will best serve your needs because the costs of both purchasing and operating each are dramatically different.
Hope that helps. Good luck with your research.
[A HubSpot Community Solution 20180421] - What Does Mailchimp Do That HubSpot Cannot?