Not really.... I've never nèeded support from Microsoft, and I rarely ever install their updates.
I think it's more likely Microsoft has learned Google, Facebook, et al's model.... give it away so that you can spy on your users and sell their personal information. And now that they can install their updates on your system whenever they feel like it, they can push out any new surveilance software they develop without your consent or knowledge.
or it is cheaper for them to maintain and support one OS. Besides that, by giving away free update from 7 to 10 you do not lose sales (who buys a new OS for an old machine?) they bind customers to their ecosystem: because who doesn’t like a company that gives away firmware updates for free?