The world is changing too rapidly to plan for 6 months in advance. Waterfall was useful when IT projects were huge and certain. Now you ain't even sure that in 6 months your business will be relevant. A company I was in, 600 devs sales hr etc, had the HR manager say "we are not structured for remote working" just 2 weeks before closing HQ for Covid and opening them back after 1,5 years. In my opinion, old, veteran, very reflective people do not accept change and accept less criticism than young people do.