Yes, but the attack is a lot of times all that's needed. I've known a handful of small companies that were attacked in court for their names on completely unjustifiable trademark grounds. However the cost to defend against even the most frivolous claims can cost tens of thousands of dollars before things really get serious. Not many small businesses/startup are in a position to take on this kind of defense. In the cases of the companies I know of, they capitulated and changed their names to avoid having to undertake the cost of the very winnable defense.

The big corps like Google, Apple, MSFT, etc. will fight it out and not really worry about the legal costs. But for startups/small businesses, this can and probably will be a growing burden moving forward.