It's not about how powerful they are. Obviously, Intel ones will always have the upper hand since AMD is lightyears behind in their CPUs.
It's about price-performance ratio. If Zen CPU costs 300 dollars and performs like a 450 intel equivalent - why pay more? I'd buy Zen in that case. That's what I mean when saying 'Intel will have to respond somehow'.
One thing they can do is lower their prices on the CPUs that somewhat match Zen's.