Adobe make the tools for creating Flash content. Not the only tools, I know, but the most widely used and supported tools. They also control the player, meaning

Adobe make the tools for creating Flash content. Not the only tools, I know, but the most widely used and supported tools. They also control the player, meaning new features added to the player will appear in Adobe tools first. They'll adapt their tools to output HTML5, sure, just like Illustrator outputs SVG. They lose the control that they had with the Flash platform, though.