Unfortunately, they won't succeed. The way their homepage is designed suggest that they believe that their reputation and brands are enough to make people subscribe. Why is it not possible to click on a channel image and have a sneak preview? Their landing page is only good for people who already made the decision to join, not to attract new viewers. In other words, they rely on youtube to expand their audience.
They aren't doomed offhandedly, plenty of original content streaming platforms make money. However they won't help with people getting crushed by YouTube; I can't just create an account and start uploading to their HBO/Netflix analog.
