Why did the BMT not build the L train on the Evergreen branch’s cut off segment?

I know why the L train wasn’t built on the Evergreen Branch in Bushwick but why didn’t the BMT build the L on the segment from Greenpoint to Newton Creek?

It was cutoff and built on, but the BMT coulda acquired the land built in its place and cleared part of it for the route. They coulda open-cut-trenched it between McCarren Park and the Cooper Park Houses and then elevated it over Newton Creek and Grand Street.

Tthe segment in Bushwick was in use, so elevating the L train over it wasn’t an option, but they coulda aligned the ROW with Wyckoff St, so why didn’t they do that or buy the remaining Bushwick segment and trench it instead?

They would be saving and using remarkable infrastructure. It also looks better than today’s L train route.