A series of vortex generators do energize the boundary layer but by the energy imparted to it by the VG blade and less from the higher speed outer boundary layer. Inside the vortex filament is a very low pressure core which keeps it attracted to nearby surfaces. You can visualize the low pressure by the way wing tip vortices condense vapor on a humid day. VG's are not free though as it requires a continual supply of (propulsive) energy to sustain the pressure deficit residing in the cores. The benefit you buy with that cost is greater resistance to catastrophic flow separation and (wing) stall.
It can be argued that the gyroscopic effect of the twisting air mass might tend to stabilize the filaments thereby reducing sensitivity to turbulence as the stream-tube filament row is passed over surfaces or even an open area such as a tractor-trailer gap. This is harder to visualize in air without introducing smoke, but witness the stability of the linked toroidal vortex in water and apply that intuition to a short straight vortex in air.