Bundling is explicitly recognized as antitrust concern. Using a monopoly in one area to undercut a competitor is what Microsoft and Google were both found guilty of by the DoJ, so it's funny you should mention them. It's not about being prohibited from developing new products, but in how you price them, and giving away things for free because you can afford to due to your monopoly in one area, and your competitors can't is the crime, or forcing people to buy both of your products together at the same time, is the problem, as enforced by the DoJ. Google should be free to develop Chrome, but funding all of its development from advertising profit and then giving it away for free because you can because you have a monopoly in search advertising is the problem, because Mozilla doesn't have search advertising monopoly money or desktop operating system monopoly to be able to give their browser away for free and fund further development from those sales. This is why, as part of the Google breakup is for them to sell off Chrome.