I dare to say, I think whoever told you that must be living in la-la land. London has around 8,000,000 inhabitants as opposed to the 2,200,000 living in the Greater Manchester region
But, don't forget the wider area. I know LBA and LPL also have Ryanair bases, but, not all routes will be available at all 3 airports.
Even to the basics before my in depth reply. If MAN is a 2m person city, but it handles on average 1.6m pax per month, its obvious they ain't all from MAN, otherwise the city would be bloody quiet!
So, its not just Manchester. For North Wales, its technically easier to get to MAN, and its even easier and quicker to get to MAN. There are not only direct trains, but, there are more per hour to Manchester than Liverpool. I know this to be a fact as I spent the first 18 years of my life there!
Then there's the Doncaster and Sheffield area, served with an Hourly train to the airport direct, and every half an hour to Manchester (with a 7 minute connection time to MAN). The Woodhead pass takes 1 hour, and when the choice is already greater at MAN, with cheaper prices, the south Yorkshire region is likely to choose MAN. (I have also seen research (not online) that shows South Yorkshire prefer to use MAN.
Its always a bone of contention on here, but Leeds and York. Again, trains direct to MAN very frequently (Im lead to believe as little as 20 minutes apart at peak time), the M62 and something you will se written a few times, more choice at lower prices. No matter how loyal someone wants to be to their local, if you see for example, someone wants to got to TFS on a Monday. LBA-TFS at £200 on a sunday, no flights on a monday, but MAN has it at £65 on the monday, its a no brainer what that person is going to do. (I have no idea if there is a TFS on a monday at either airport, it was just an example). People vote with their feet. This is why LBA is a 3m pax per anum airport, whilst MAN is close to 19m pax per anum.
Then theres the West coast. Down the M6 and then 10-15 minutes along the M56 and your there. Again, there are direct train links to the airport every 30 minutes all the way up to Glasgow (hourly to Edinburgh), or, you can easily connect at Warrington Bank Quay or Crewe for Manchester.
Liverpool itself. Yes, LPL does have its own airport, but, there is no long haul at LPL, and a greater choice/selection at MAN, so, quite a lot shimmy over to MAN.
Again, motorways and trains make it 50 minutes away, and, I have seen myself how busy the Liverpool Lime St-Manchester airport train is, it can be PACKED!
Last but not least, you have South Cheshire down to Birmingham. You would be surprised how many Brummies you see at Manchester Airport. Paul Kehoe of BHX himself has said up to 60% of BHX's catchment is heading elsewhere to catch flights. The majority go to London and East Midlands, but, a fair few head up the M6 for exactly the same reason as Liverpool, more choice at a cheaper price.
I find it difficult to see how Manchester could handle such an operation without massive reductions in operations from other airlines
Dont forget, Ryanair serve a LOT of point the traditional carrier will never ever serve, and that Ryanair can aim for.
Would BA serve MAN-Lodz? Would Monarch serve MAN-Kerry? Would Jet2 serve MAN-Kaunas?
There is still a lot of potential at MAN Ryanair could achieve before it really starts to tread on other toes too much. Just look at Ryanair's route list and you would be hard pushed to find another carrier to serve them.
I am not expecting the full 25 units, I must admit, but, I do believe there is scope for 15 based units. Jet2 is up to 10 based units and they only offer 36 routes, so, shows you how there is scope.
Didn't even Thomson Airways pull their base at Stansted for example!
Nope, I can assure you that is still there and going strong. Its recruited new Cabin crew this year and is doing so again next year.