A lot of people have struggled with this. No charter appears to be forthcoming, because the interests of the cloud providers lies in locking their hardware users in, based on the potential future profits to be made from subscribers. The more dependent you are upon their cloud, the more you'll be theoretically willing to pay for continued service (note that payment already includes non-monetary transactions such as targeted advertising and data collection.) So don't expect any of the cloud-based solutions to champion an exit strategy.
So for now, you can overcome your reluctance by taking matters into your own hands. Your best defense is to purchase independent items that comply with standards (open or proprietary), as opposed to being run by proprietary clouds.
Let's look at three examples: cloud-based, proprietary network, open network.
AssureLink is a proprietary wireless network that uses a home hub to connect to a cloud-based service to provide remote access to one brand of garage door openers. When these openers were released on the market, a subscription to AssureLink cost $19.00 per year, and there were few sales. The company dropped charging for the service so they haven't gone away, but there is always concern that once they've saturated the market, the company will have no reason to continue the service, at which point the devices would become useless.
This concern is not without merit.
Pebble's recent acquisition by Fitbit has thrust them into the spotlight, but Revolv was the previous poster child for IoT devices being bricked by their parent company. The Revolv home hub connected to a proprietary cloud service. Google bought Nest, and then bought Revolv to get some of the people. They saw Revolv as splintering the home automation market away from Nest so they shut it down, bricking every Revolv home controller.
Is this true for all cloud-based hardware? Apple, Google, and Amazon are all as stable as any provider can be. But Revolv sure looked good when Google first bought them; Nest is reportedly in disarray internally (and Google's new hub is pitted directly against Nest's philosophy), and you only have to look as far as Microsoft's Zune or Phone to see that being big doesn't mean that a centralized service will remain successful over the life of your devices.
Proprietary P2P network standard
Z-Wave is an example of a proprietary mesh network technology. Z-Wave devices can talk to each other, but each device requires a communications chip licensed by a single company. Development and per-chip licenses are ridiculously expensive, so the price of the devices will never come down until the patents expire, and even then only if someone else enters the market to compete with them. However, once you have a Z-Wave device, it will continue to work with new and old Z-Wave devices.
Open P2P network
WiFi based cameras are a good example of devices based on open network technology. Apps for smart phones can connect directly to the camera, no cloud required, no expensive licensed technology. However, these have drawbacks. In order to use these devices without a cloud, the installer has to configure their router/firewall to enable remote access. And as we've seen with the Mirai botnet, these devices are responsible for their own security but not all do a good job of it, and they even put the rest of your network at risk.
The future with Open Source
The open source answer to this are projects like OpenHab, Domoticz, mosquitto, and others. Instead of a proprietary cloud, you run the P2P devices from your own server. Only the server is exposed to the internet, and for the most part these are positioned to be better hardened. At this point this approach is still very much in its infancy, and all the solutions so far require some technical skills to set up and maintain a home network.
However, by focusing on P2P devices today, whether they use an open or closed protocol, you are at least investing in building your own infrastructure that will work free of the dependency on proprietary external services. You can even get started with a proprietary home hub, as long as the devices are communicating via a P2P standard that exists beyond a single company. The open source solutions can't get any worse than they are right now, and are rapidly improving.