It's not 'competition'.
It's carnivorous, predatory.
Consider shifting gears and seeing all of this through the lens of 'power'.
There is no such thing as open/free markets when there is massive power asymmetry.
Anything that a weaker entity produces, will be 'taken' by a more powerful entity via all sorts of mechanisms.
The 'point' of IP/Open Sources liscencing can be whatever anyone wants it to be ...
but consider this: if the 'game' is on a tilted field, then almost all of the economic value goes into the hands of those with the power to reap the surplus - not the creator.
The 'owner' is who has power.
The Kings didn't rule by arbitrary decree - their money came from owning all the land. It doesn't matter how hard you work, how hard you innovate, how much surplus you create - if the landlord says 'I want all of that' and you have no choice.
Your Rent = All The Value of the Stuff You Create with a bit leftover for you to survive.
That is entirely done through legal ownership - not through some kind of forceful cocercion.
Control of distribution, access to financing, entrenched supplier / buyer relationships, barriers to entry, regulatory capture, economies of scale - all of that makes some systems unassailable without some degree of power.
Purely through the lens of power - Open Source is like 'commoditizing' a tiny little part of the system, where the surpluses will get pulled in by the most powerful entity.
In this case: Amazon.
Anyone writing software and 'making it free' - that Amazon can use - is working for Amazon for free.
Again: if you want to see it way.
If you just like 'making stuff' that's perfectly fine as well.
But - the moment you see this as a 'means to income' - then - it's a 'power dynamic'.
This is why better/smarter IP laws should help smaller players.
The whole point of these things is to try to enable actual competition - which is not 'feed David to Goliath' - its supposed to give David a chance.
The 'changing of license terms' by some small vendors is the result of Amazon suffocating them - it's the power system finding it's 'equilibrium' - where the 'creators' are snuffed out - or 'better yet for Amazon' keep working for free.