The step from prototyping to mass production is huge. People need to visit factories, set up spaces for assembly lines and SKU's.
Facilities need to be changed to meet standards etc. etc. that is a main reason why so many Kickstarters do not launch or have enormous delays.
So make sure you are confident that they can deliver quality and bring the product to a mass audience.
Symme3D seems to be a good example, it has been two years with big promises and great funding and their printers are still not launched.
While Snapmaker so far is a good example of the opposite, they have their devices mass manufactured with only some minor improvements needed to be done causing little delay, and have been very active involving the 3DP community. You have to go into a lot of depth before investing in KS companies.