If you build your recruiting and training around wfh, it can be as productive, it won't be if that's not in your DNA
It's also a recruiting benefit just like anything else, so it's not just a productivity question. You also have to ask if you can recruit the talent you need with no wfh.
Anyway, places that started wfh I've seen do very well. I've seen very few successfully transition though.
Hybrid is easy.