What if Tencent after being told no to the purchase of Bluehole - instructed Epic to make a clone so that they could undercut PubG in the West - and more importantly, bring a BR game to China first. And the "we're just fans of the genre" is just masking the truth.
Doesn't make it illegal perhaps, but pretty scummy.
Even assuming it was that deliberately malicious if you aren't reflexive enough to the needs of your audience, and someone else scoops them up, that's on you. It isn't for the industry to step back and let them take as long as they'd like to satisfy their consumer's wishes.
They're only entitled to their headstart. Like Minecraft they have to keep up with competition or be left behind.