Asked another way, why would an relatively small individual country be any less happy with 760 channels than a centrally coordinated continent? I would have thought a small country would need nothing like 760 channels, individually.
If by bad luck two stations in neighboring areas/countries picked the same channel from 760 available channels and found a conflict, wouldn’t one of them just change to another frequency assignment? How would 2280 channels to choose from make that process any more rigorous? Is it just a matter of the odds based on random selection being more in favor of a good outcome & no conflict?
AFAIK there are relatively large buffer zones around the country borders where individual frequencies are allocated exclusively to one country. That seems to cause quite a bit of allocation inefficiency.
Furthermore, there seems to be a school of taught that propagates increased capacity by making ATC sectors very small, forgetting that there’s a practical limit in sector size due to the frequency change traffic. Already, for my relatively slow plane, sectors around Munich require frequency change every few minutes.
I don’t know about frequency allocation specifically, but I do know that this kind of optimisation problem is harder than it looks. You don’t want a heavily optimised scheme because if you then add a new sector it may cause an avalanche effect where you have to change a lot a frequencies.
Anyway it is downright silly that frequency allocation can’t be done on a European level.
You have to ask: how does it work on 25kHz in the USA? I mean… they do have one or two planes there, more in some places like LA, and ATC of sorts 
I seem to recall that the biggest issue is actually company frequencies. Frequencies that airliners need to talk to their company about scheduling and whatnot. As these should be usable across, essentially, the whole of Europe (or even further away), and are used at FL300+ (thus have an effective range of several 100s of miles) they are effectively exclusive across a vast area.
And the same applies for frequencies used by ATC to control traffic at higher levels. Because VHF is line of sight, these signals can be heard 100s of miles away, and may interfere with communications over even larger distances. So if you allocate a frequency in, say, Amsterdam, the nearest place that can also use that frequency might be in Madrid or even further away.
Frankly I’m surprised we’ve been managing with just 760 frequencies for so long, considering the incredible growth of aviation in the last 30 years or so.
Wasn’t the need for such “company frequencies” much reduced with the introduction and, AFAIU, general use of ACARS?
I guess there will always be times when you simply want to talk to somebody about something. So every company would need at least one company frequency and that frequency would have to be pretty much exclusive across Europe. How many airlines in Europe? A hundred? That cuts deeply into the amount of available frequencies.
A lot of airlines use the handler’s frequency at destination for routine reports like fuel, connecting pax,…
