Security aspects aside, that's fine - what isn't is the inability to run that external server yourself.
Imagine if instead of using "proprietary cloud xyz" for a particular IoT product, you could spin up a cloud server or container up somewhere and install it yourself - and as long as you pay for the server, you have access.
Let the consumer decide based on their "expertise" level what option they want to use - but the option should be there, and included in some form with the product itself (maybe on an sd card or something), so that they could at least transition to that should the company go out of business. Ideally, the system would be open source as well, so it could be expanded.
