There are number of different platforms that are designed to help you with what you are after that provide a varying degree of functionality. Some focus just on the LMS side of things, some focus more on marketing, some like our platform LearningCart (www.LearningCart.com) try to provide everything you need (website, LMS, ecommerce, reporting, etc).
One thing many people don't know when they get started with elearning is there is actually a standard for developing web based training (SCORM). Although it sounds great to use a tool like teachable, those sorts of tools are using a proprietary format that locks you into their service - If you ever want to use another system you must rebuild ALL your content.
If you develop your training using SCORM you can take your content and easily load it into the 1000's of LMSs that are SCORM compliant. Long term it gives you options and it also lets you much more easily license your content because most large corporations (and schools) are already running a SCORM compliant LMS internally. Some of the popular SCORM compliant course authoring tools right now are captivate (by Adobe), articulate, and ispring. These are desktop applications that are way more powerful than the web based authoring tools and have a long track record of support and feature expansion. Again if you develop your content using one of those authoring tools in the long run you have will a lot more control and options.
Hope this information helps, happy to answer any follow up questions you might have or setup a call to honestly assess your needs and recommend what platforms might be a good fit.