The binman chronicles
Player Valuation: £80m
Well there seems to be limited space in the concourses so may be that or some other design reason. Can't see it being by choice.
It is for space and cost reasons. If you have them further back then you need an array of staircases to get down to the bottom which will obviously encroach on the space available on the lower concourse. Or you raise the concourse but if you do that the space available starts to diminish as the stand angles backwards. Least the latter way you can probably share the upper tiers stairwells but these would need to be made larger/more of them to cope with the increase in footfall and it will take longer to evacuate in an emergency.
The Cardiff City Stadium has similarly low down entrances/exits into the bowl. It is just far more cost effective.