O2 EDGE Coverage Question

At the announcement for the UK iphone O2 stated that they would hopefully have 30% EDGE coverage.

So this would mean they have coverage in the main urban populations only.

Now my concern is that if Apple plan to release an iphone with 3G or HSDPA/HSUPA in the future then what does that mean for O2's EDGE rollout?

O2 have spent £billions on their 3G network over the last few years. So why would they spend more money rolling out a lower speed network if Apple have a new iphone in the pipeline?

Will O2 do just the bare minimum rolling out an EDGE network on the hopes that Apple bring out a 3G version?