It's all down to expense. More floors adds more structure and more vertical transport (as they like to call stairs, lifts, escalators). Even Spurs big home end only has 2 floors of concourses. They tend to save the multi-floor concourses for the higher paying pundits. It's shame for all the reasons expressed, but it will also be a long walk for those on the rear rows wanting to go the toilets after their prematch sesh.
Similar for the increased tkt prices. There are only approx 450 box seats at BMD and 4500 mainly corporate lite total to help cross subsidise the GA seats, in a stadium that has cost roughly £15,000 per seat to build. There are over 2k box seats at the Emirates and almost double the corporate.... without a sugar daddy, the ROI can be staggering for any large new build and usually requires the corporate sections to do some seriously heavy lifting....