That seems to be a compromise with the retail sector in my opinion.
Codemasters know that PC sales need to switch to digital distribution as the retail sector is yielding lower and lower margins for them as time goes by.
Maybe now we will start to see lower digital distribution pricing, after all, it is the retail market throwing their toys out of the pram which is the reason why digital prices have been inflated anyway.
Seeing as of the few stores remaining who do still sell PC games, they very rarely sell "back catalogue" stock and generally sell new releases and maybe the current top 40 if your lucky along with the trillion "casual" PC games.
So, the current thinking is spot on in my opinion.
Retail sell the majority of PC releases at launch in the opening few weeks, after the initial release, they generally drop off the shelf to make way for the next "new thing".
By selling digital only, the retail sector will no longer have the "stranglehold" over pricing which they have had for soo long while at the same time, for the time being, allowing those who who would rather have the more "traditional" case and disc or limited internet connection the ability to do so untill intial stocks are depleted.
The Steam pricing for F1 2010 (£26.99) pre order (£29.99 RRP) is more than fair in my opinion seeing as Codemasters have sold previous "New Releases" for the FULL RRP £35 mark and MAYBE the lower pricing may just have something to do with them "releasing the shackles" from the UK retail sector, which is mainly Gameplay (GB) Ltd who have (I am assuming) been the ones throwing the spanner in the works of Digital Distribution by likely refusing to sell certain other products from the same publisher on more profitable platforms were they to try and make digital distribution competitive.
Point to note, the RRP of the game is £34.99 yet both Steam and Game.co.uk have it listed for digital download at £29.99.
This has been a change in the PC market which has been on the cards for a while, it will happen with the console market too, just as allways, the consoles will be soo many years behind.