The amount of other phones in the cell affects what are the most important characteristics of phone to optimize for. The issue in here is about the minimum power levels which mainly affect the radius of the cell. However as the amount of other phones have gone up the situation where there is an empty cell where the radius could be an important factor has gone to be not so important any more. Nowadays it is all about signal to noise ratio at higher power levels that matters in a busy cell and that is not what was studied in here. The issue about reduced radius of a cell has been fixed in network design by putting up more basestations which are needed in any case to support the increased amount of phones in cell. So to summarize. Yes the phones are worse in this respect but this particular performance metric is not so important any more as it once was and phone manufacturers have allowed it let it go worse as nobody really cares about this one any more and other things are more important now.