Tom if Mr Academic is frustrating you so much with the lack of messaging now, what are you hoping to get out of persevering with him? It's totally understandable why you're frustrated; I think he's actually really quite rude and arrogant to leave you hanging for days for a simple response, as if your time isn't as valuable as his. This is clearly how he is though, he's not going to miraculously change into a good - or even average - communicator, and you say that (understandably!) that is what you want. At this point he should be on his best behaviour trying to impress you so either this is his best, or he just doesn't really care or value your time.
Lots of us have very busy lives but it takes less than a minute to fire off a text if you want to do it. There is taking it slow and not messaging 24/7, and then there's taking the piss and leaving someone hanging until it suits you. I'm not holding Mr DiamondMine up as some kind of paragon as I don't really know him yet, but whilst far from OTT on the messaging - we never spend hours back and forth - he has been consistent, has messaged most days to check in right from the start, and never leaves me hanging, except when he got admitted to hospital but that is obviously a different scenario, and he apologised profusely as soon as I called him on it (which I wouldn't have if I'd known where he was!). There might well be people who it suits to only be in contact once a week or whatever, but it obviously isn't what you want which is the concern, and it should be fun at this stage, not continually frustrating or saddening...
Speaking of Mr DM, we went to the cinema last night and first moves were made, we have officially made it to first base
He seems really lovely, he messaged first thing this morning to say hi and that he had a great time. Hopefully seeing him again at the weekend.