1) Each website will inevitably have its own API that is incompatible with every other similar service. With service APIs, no one will bother with standardization on anything but the base protocol, because no generic standard satisfies any individual service's full functionality.
That's pretty much a description of how web pages worked just fifteen years ago. Nobody misses the days when most websites were designed for IE or Netscape and you couldn't make a website that worked well in both without taking quite a few special behaviors into account. Today, Microsoft is pushing Edge, Chrome has a significant market share, and Firefox's trailblazing changes made it normal for a browser to use tabs and block pop-ups by default. Not only has standard behavior improved for the better, the industry leaders are all trying to adhere to standards.
Your instant messaging providers would still be incompatible with each other, for instance, because company A wants a whiteboard mode and company B wants custom emoticons.
Recognizing that is the state of things doesn't mean it will stay that way forever. Consider how many websites have realized that managing their own authentication process is a bad idea. There are still plenty of problems, but it is becoming normal to use an inter-operable system. Right now trapping people into a single messaging system is a business model, but I don't think it will stay that way.
2) Because it's easier/cheaper/faster, everything will depend on some company being in business and providing their service. If somebody makes a service that does text-to-speech extraordinarily well, for instance, and does it as an online API call instead of locally on the device, then if that company goes out of business the service dies with them and everything that depended on their particular text-to-speech engine would stop working.
Unless it's an open source service, then five more will spring up in it's place. If that text-to-speech service is widely desired, an open source version is guaranteed to spring up eventually.
Wait a moment... aren't these types of problems happening today? Business as usual then. Carry on.
Business as usual is widely panned, but we already live in a world where business as usual has radically changed in just a couple decades. I carry a computer in my pocket that is massively more powerful than I could have predicted twenty years ago. Yesterday I talked to it and got an answer. When I was a kid, I couldn't have gotten that answer without a trip to the library and possibly weeks of waiting for the library to get the book exchanged from another geographically distant library.
Business as usual for the average person is change, not measured in generations or even decades, but measured in months.