The thing is, there effectively has been a lot of consolidation of the EU telecoms market, even with its fragmentation due to roaming tariffs. The only thing is that the likes of Vodafone, Telefónica, Orange, Deutsche Telekom, TeliaSonera, Tele2, Hutchison Whampoa, Telenor, Airtel, Swisscom, &c., have had to establish subsidiaries in the various member states up until this point, and what we're likely to see is that the parent companies will start consolidating their national subsidiaries.

I doubt we'll end up with anything near as bad as the situation in the US, where they're left with effectively four operators of note operating two incompatible sets of standards, given the EU's greater overall diversity: language barriers, if nothing else, place limits on population migration, so smaller telcos with a firm footing in a particular market might be protected from larger multinationals eating their lunch completely.