First, a shield doesn't help so much. The only effect is making archers focus on another defenseless prey. They still can shot feet or head, or the sides of a shielder.
Second, ladders weren't removed, making a large part of archers go in places safe from cavalry, without any teamwork involved. Literally taking zero risk from anything except other archers.
Third, everyone is running in mail or less. Only people that do leeching or were very rich are able to pay plate from time to time. You can't avoid ranged fire much, which means armor is your best protection against it, and it was reduced to dirt since upkeep came out.
Fourth, there are no more open maps where cavalry can succesfully counter archery. Every battle happens in a village or even a town (
) with vantage points everywhere.