>>1790170they're actually more comfortable, over the years they figured out the far back saddle position wasn't as good as they thought
the position of the rider is far more forward now, they sit nearly over the bottom bracket
doesn't have much to do with aero, they can simply generate more power, more efficiently because they're MORE comfortable
there has similarly been a trend lately in moving aero bars up on time trial bikes, puts the riders in a more comfortable position (at the tiny cost of some aero)
it has lead to much faster times
compare this pic of van aert to how cancellara used to ride his tt bike with the bars slammed
aero plays a limited role, comfort is far more important