I would love to see this functionality added for HubSpot LMS as a product offering. HubSpot Academy sets the bar high for an LMS from a user perspective and as the need for online courses is growing for clients, it would be fantastic to have a HubSpot LMS add-on / product rather than having to try integrate third party tools.
I'm honestly surprised this hasn't been done yet. Hubspots ability to collect data from users makes creating an LMS a no-brainer. I doubt they'd break a sweat using current systems to create it.