I think most long term fans are aware that however bad the customer services is, people who go to the ground will get into the stadium for the match. We played Paris a few years ago and my ticket hadn’t arrived (paper tickets for 93:20). I just showed my season card (for League games) and was let in.
I think the bigger issue for the club and attendance income, is whether Blues will go to the trouble of bringing extra people to Cup games. I can see the increased complexity of doing so hitting attendances.