Furthermore only vascular endothelial cells count (not all others including lymphomatic endothelial cells) because blood only gets in contact with the vascular type and all drugs and immune cells we are talking about here are in the blood environment.
That is totally false. The antibodies and drugs under discussion most certainly NOT restricted to the blood or blood environment.
The life span of endothelian cells (time from being created till the apoptotic cycle starts) is months to years.
What does that or the lifespan of other cells have to do with anything?