RE: ...there is no bin space left because of the binhogs and blind-eyed flight attendants.
The problem with some aircraft is one of geometry. If carry-on bags are 14 inches wide and seat pitch 31 inches, you can fit 31/14 = 2.2 bags per row. When you have 3 seats (e.g. narrow body 3 + 3 seating) in that row, you can not fit everyone's carry-on inside the passenger compartment.
Similarly in a large wide body say 3 + 4 + 3, you have 10 seats per row and with overhead compartments on each side of the aisles, you have capacity for 8 bags for those 10 seats. If everyone does carry-on, it would be gate check time for the bags that cannot be accommodated.
It's geometry, but bin hogs putting bags lengthwise because the bag is too long make the situation worst.