Do they not understand that they'll lose the old audience?

No, they don't understand that. They believe they'll gain more than they'll lose and they take the old audience for granted. Because let's be real, it's pretty rare that an IP loses a significant majority of its audience all at once to make a problem. It usually takes years of it.

Take Doctor Who for example. We can see the woke elements all the way back in Matt Smith, but it wasn't until Capaldi and Clara that people really started to complain, and it wasn't until Whitaker that people actually started leaving en masse. It took years.

The idea is that they can gain more than they'll lose. They're hoping it will be like a transaction. They're hoping they'll loose something like 10,000 followers in the hopes of enticing in a new 50,000, but it's just not going to happen. And that doesn't even look at the types of fans they're losing vs gaining. The 10,000 they lost? Probably more likely to engage in extra purchases and merchandise. The 50,000? Probably casual. But they don't care, because it's about making a cultural impact. And those 10,000 are the unwashed masses, not the refined culture. Ignore of course the fact that mass media is and always has been largely shallow.