Considering DC isn't investing a big movie budget, taking a risk for a greater return is worth it. I'd argue you have the wrong idea here. Getting into another market is fine, but let's be honest, breaking into Webtoons is not hard. It isn't some complex foreign medium. DC Comics is first and foremost in the business of building brands and expanding their brands. Doing R&D so they can be more successful at other ventures, be it merchandising, film, tv, gaming. You name it.
Their competitor takes risks all the time on a variety of properties. Some pan out, while others do not. It's a smarter business play if you're trying to grow for the future. Not only is it R&D, but it's a look at another brand or franchise. Marvel does not lead with Spider-Man all the time despite him being their most popular hero.
The dangers of playing it safe aren't sudden, obvious, and dramatic. They don't make headlines. They develop slowly over time and are almost impossible to pinpoint. Not taking risk is a bigger risk. In this brisk-paced world, the only strategy that is guaranteed to fail is not taking a risk. The cost of inaction is often higher than what we can imagine.
Look Kodak, almost going out of business for not embracing Digital.
Time goes fast. Nothing lasts forever. I'll always be in favor of seizing the day. Otherwise, someone else will take your lunch.
Look at: Blockbuster, Nokia, Xerox, Yahoo, Myspace, Macy's, Border's, Toys R Us, TiVo, etc., etc., etc.
"Playing it safe in business" is very rarely the best choice for long-term success.
The point being is you seize the day. DC might have missed an opportunity here. I'm not assuming DC is going to blow up all over Webtoons. That'd be great, I guess, but just like the DCEU, nothing is certain.
End of the day, it's just a difference of opinions. I'd rather be Steve Jobs or Elon Musk than Kay R. Whitmore.