Perhaps, but what really happens, and what's a good business plan are two different things. In this case a talented programmer was probably hired or allied with the company on the basis of demonstrating a flashy, single platform program with a year or more of code development behind it. That's a lot of code to reverse engineer for another OS.
Graphics software is different than business oriented software. With business applications, it's pretty much a matter of translating dialogue boxes which are already very similar in Mac and Windows api's, and there are good software packages that can automate a lot of that. OTOH, graphics software has to work very close to the hardware, and it that area Windows and Mac api's are very different and both rather esoteric in their design. The longer they wait to keep an eye on both platforms, the harder it gets until finally they're stuck in single-platform mode. Yes it's the common case, and yes it's a huge vulnerability to business success.
Anyway, it's another David and Goliath match. In the real world, David almost always gets stomped. Adobe has a truckload of software patents, many unworthy of ever being granted, but ammunition none the less. The new guys could be badly harmed simply by the time needed to process subpoenas and give depositions, much less in court.
