There are plenty of reasons to choose a point in the space denominated by the axes make/adapt-existing X insource/outsource X proprietary/open . None are zero cost unless you really think your platform is good enough that enough others will write for it without you doing anything.
It's possible that you would chose to write your own because nothing in the market is even close to good. It's possible that you would open source it in the hopes that it becomes standard and that others will add new features that you will benefit from too (this is not a zero-cost option either). It's possible that you would even keep it proprietary because that's cheaper. But given the way Amazon operates it's pretty clear that they offer their own proprietary services to lower the barriers to adoption ("simply offer a better option") and raise the barriers to switching.
I don't see anything wrong with this strategy legally or morally, though I mostly avoid amazon proprietary tools because the risk of locking is one I'm not willing to embrace. There are of course situations where they aren't a problem (e.g. a tool with an anticipated finite lifetime: the cost of lock in in that case is essentially nil).
There are plenty of reasons to choose a point in the space denominated by the axes make/adapt-existing X insource/outsource X proprietary/open . None are zero cost unless you really think your platform is good enough that enough others will write for it without you doing anything.
It's possible that you would chose to write your own because nothing in the market is even close to good. It's possible that you would open source it in the hopes that it becomes standard and that others will add new features that you will benefit from too (this is not a zero-cost option either). It's possible that you would even keep it proprietary because that's cheaper. But given the way Amazon operates it's pretty clear that they offer their own proprietary services to lower the barriers to adoption ("simply offer a better option") and raise the barriers to switching.
I don't see anything wrong with this strategy legally or morally, though I mostly avoid amazon proprietary tools because the risk of locking is one I'm not willing to embrace. There are of course situations where they aren't a problem (e.g. a tool with an anticipated finite lifetime: the cost of lock in in that case is essentially nil).