Thanks for your comments, GB. I have indeed been involved in the planning and implementation of a number of res systems (including Navitaire), and I'm happy to be able to shine a little light into a dark corner!
I think the reasons that we're starting to see slower and slower res systems across the board (and I won't single out Ryanair!) are two-fold:
Firstly, we're making more and more demands on the databases. In the old days, when people were using old-fashioned res systems, at the dawn of low cost, you asked for a flight from A to B on Thursday 8th, and that is what you got. It didn't show you the 7th, or the 9th. Just the 8th. Since then, we've just screwed on extras - day either side, low fare finders, even alternative routes ("Alicante flight full? Try our Murcia service" etc). We've chucked in different fare classes ("want more flexibility? Click here"), and all sorts of other rubbish. All of which slow the systems down.
Ryanair have resisted most of this - but one could argue that they have the second problem...
When systems like Navitaire were written, they worked on the basis of being used to power airlines that had, say, 50 aircraft. Since then, some of their airlines have grown like topsy - eg FR, U2 - and I would wager that some of these systems are starting to strain a bit. The choice then is simple - spend lotsadosh on systems upgrade, reduce functionality - or lock the people who are hammering the databases for the hell of it (eg PCSs) out. Guess which gets the vote?
There's a whole range of res systems out there - the market leader in low cost is Navitaire, but I think we're going to see the growth of new generation systems soon (eg Radixx), and perhaps even the smaller systems may power-up (eg AirKiosk). Fingers crossed.
In the meantime, we're going to see less speed with more features...
As for cheap flights - the problem is in essence that you are trying to drive the database backwards. The vast majority of customers will know where they want to go, and roughly when - and the database search functions are built that way. Ask the database for the lowest fare, and that's a new search function - ask for lowest fare on all destinations (since you don't care) and that is a huge processing task.... your best bet is narrow your search down a bit, and use the airlines that have "fares by month" grids (bmibaby and easyJet to name but two)...