I'm a bit confused by your objection to "platform lock-in." Presumably a person or company who has chosen to use this service understands the technical limitations and features it entails. That includes understanding that AWS may in fact implement this service differently than other providers do and that a future move might entail some non-trivial effort. That isn't platform lock-in in any meaningful sense.
Besides, what makes you think you would be prevented from moving all this to another provider? From the FAQ (https://aws.amazon.com/cognito/faqs/), it seems that Cognito data is stored in a straight-forward Key-Value scheme. That's about as easy as it gets when it comes to data structure.
Moreover, the actual service itself would almost certainly be implemented differently with another provider. Why should Amazon, or anybody else who offers similar "menu of services" cloud computing, make it easy for you to do so (they make money off of you not moving)?
> Presumably a person or company who has chosen to use this service understands the technical limitations and features it entails.
That's a pretty big assumption to make. People, even technical people, make assumptions all the time that they'll be able to get their data out of a system and then aren't able to at a future date.
Because the best way to get a user to "move in" is to make it easy for them to "move out". It's actually in Amazon's financial interest to make it easy for people to move off of their offerings.
This is one of our core values and while we get odd looks from investors or MBA-types we know that it's the right move to make in the long run. This is the way things are moving and I hope that more companies will go this route.
The thing about casual discussions like that is it's easy to build a narrative without actually providing much substance. Joel's essay doesn't discuss Microsoft's "barrier(s) to exit" that Office itself didn't give up completely until last year (cf: Open Document), and Windows itself has yet to yield (it is still the dominant OS, by far, in the desktop and laptop markets).
Sure, "barriers to exit become barriers to entry" is applicable in some contexts, and for some part of a potential market it will be the barrier that keeps those customers away. I wouldn't dispute that. I would dispute that "barriers to exit become barriers to entry" be treated as a universal maxim applicable along all businesses and products. It's just as much of a strategy mistake to make as assuming the barrier can't exist in the first place. It ought to be considered; not treated as a key issue until or unless the data suggest it should be.
Besides, what makes you think you would be prevented from moving all this to another provider? From the FAQ (https://aws.amazon.com/cognito/faqs/), it seems that Cognito data is stored in a straight-forward Key-Value scheme. That's about as easy as it gets when it comes to data structure.
Moreover, the actual service itself would almost certainly be implemented differently with another provider. Why should Amazon, or anybody else who offers similar "menu of services" cloud computing, make it easy for you to do so (they make money off of you not moving)?