>But, a year later with Windows Phone 8, Microsoft told all the developers that the investments they made in Windows Phone was a waste of time because none of their apps will work on Windows Phone 8.
Isn't that completely false? All WP7 apps run on WP8, bar a few minor incompatibilities.
99% of WP7 apps worked perfectly well on WP8. The only ones that had issues were usually the ones that had managed to get exemptions from Microsoft to use underlying private APIs that may have changed (hence private).
He's probably got the timeline a bit mangled in his head and is confusing app compatibility with device compatibility (which WP8 did break). Although XNA apps did get stranded in a legacy quirks mode.
Isn't that completely false? All WP7 apps run on WP8, bar a few minor incompatibilities.