Why not equip now? Because there isn't an area where ADS-B is required in 150 miles of where I live. When I finally get out of testing my experimental, and if I decide to go to one of those places where it is required, I'll have to install it. But if I just fly in the local area, I may never need it.
Too many of the FAA's trains that left the station have been on their way to a train wreck. I still remember the 1988 transponder requirements that were rather quickly rescended.
There was a point along in there in which we were told we'd all need to replace our mode C transponders with mode S. King Radio believed it, and spent a lot of money creating a Mode S transponder which few bought, because the FAA changed their mind.
I respect your opinion, but until I really need this, and I see just how the mandate plays out, I can't see spending (in my case) about $3,000 to comply. This is not a trivial sum for most of us.
I'd list myself as another old pilot, but I've only been flying for 48 years.