While I agree with your analysis I disagree with your conclusion - I still say it's irrelevant.
Yes, it would be possible to engineer a situation in which too much memory is in use by services but it just isn't going to happen in real life so the fact that it could be done doesn't mean it will ever happen. Users need not concern themselves over situations that don't actually occur in practice.
I just checked on my phone and services are using a grand total of 110MB and only two of them are more than 10MB. Meanwhile, I have 44 cached processes (some of which relate to apps that I haven't used for several days) and still have 160MB free. I have never worried about how much memory was in use and if I had installed five times as many apps that run services in the background, I still wouldn't need to.