You miss the point.
The point is that while the property owners can do what they like, the prospective *tenants* may have a very different outlook on the matter.
I doubt the property owners would want to build two more 110 story buildings only to have them remain mostly empty in perpetuity because the financial players have decided there's no good reason to all gather in one spot anymore (and good reasons *not* to).
Yes, it is likely that we have reached the time when, thanks to technology, serious thought should be given to dispersing workers instead of shoe-horning them into a vertical space. Think about not having to commute, possibly even working from home etc. It's just a matter of management getting over having to see faces in person every day. Again with the right technology, there are plenty of ways to check the work output of offsite employees.
I believe the NY and NJ Port Authorities owned the WTC or most of them? IF it was financially possible to leave the crater as intact as possible as a memorial, that would be my first choice for the future use of the site. Of course that would require serious commitment to dispersing workers back into or closer to their bedroom communities in NJ, Connecticut, Long Island etc. I know that NYC will resist such changes because of the lost tax base but it's coming anyway, so why not get ahead of the curve instead of replacing the WTC with the world's most expensive white elephants?