I think it's mostly transmissions and other non-turbo effects that cause these contemporary lag complaints. With all the fleet mileage requirements, there are

I think it's mostly transmissions and other non-turbo effects that cause these contemporary lag complaints. With all the fleet mileage requirements, there are much higher gear ratios for cruise and coast modes, so the engine can be bogged way down near idle speeds. Also, there are more software based throttle controls and interlocks. Some of this has to do with heavy-handed reaction to prior "unintended acceleration" panics, and some is just part of all the modern traction/stability control and efficiency programming. The programming can get utterly confused and fail to dip back into a ground state where it is ready to accelerate. People doing various combinations of heel-and-toe or other transitions between braking and acceleration, including rolling stops, may get their car into a different mode than they would want, and the recovery from this seems like "turbo lag" or worse.