I'd love to see another player in the GPS watch field, but there are couple obstacles any new entry is going to need to contend with.
First, there's already a relatively diverse market out there. You have Garmin, Polar, Suunto, Coros, and (to a lesser extent) Apple. They all offer something a little different and appeal to different people. What part of the market does Timex/Casio go after?
Garmin is the market leader because they got in the game really early and therefore have the most polished product. They also offer some things that others don't, like music storage and a HUGE product lineup that caters to almost everyone who does anything outside.
What does Timex/Casio offer that Coros doesn't, beyond brand recognition? Coros is already the value option that provides the features that a serious athlete would want. In fact, if Coros didn't exist and you asked me to describe what a Timex GPS would look like, it would be a Coros.