They haven't said why, but the reason seems commercial and not technical.
Unless a service is bringing in millions or maybe tens of millions of $$ in revenue, a big company like IBM would not find it to be attractive enough. And some big manager one day is gonna cut it down as part of 'house cleaning'.
Whereas for a smaller startup, that same 'millions of dollars' in potential revenue might be a VERY attractive opportunity.
To paraphrase Bezos, big company's need for scale is the startup's opportunity.
Unless a service is bringing in millions or maybe tens of millions of $$ in revenue, a big company like IBM would not find it to be attractive enough. And some big manager one day is gonna cut it down as part of 'house cleaning'.
Whereas for a smaller startup, that same 'millions of dollars' in potential revenue might be a VERY attractive opportunity.
To paraphrase Bezos, big company's need for scale is the startup's opportunity.