Well that sucks.
Crash Bandicoot 4 already exists. It's called Crash Bandicoot The Wrath of Cortex. Really pissed that they're retconning it out of the series rather than remaking it too, since it was a good game!
Wrath was only ever Crash 4 in Japan.
For the rest of the world, we never had Crash 4. After releasing the Nsane Trilogy, calling the next game Crash 4 just makes too much sense.