Not only because LCC cost for F22, but also purchase cost ! F22 was sacrified, as the Leclerc main battle tank in France (400 units instead of 1400) because of the collapse of USSR mainly.If you think maintenance of Western fighters is cheap then you are living in delusion. Do you know initially USAF wanted to procure 750 F22s but atlast settled for just 189? Guess why? Due to high cost of maintenance!!!!! Same goes with other Western fighters like eurofighter typhoon or Rafale despite they are 0.5 gen older then f22.
And surely there are other factors too. IAF chief has clearly stated that MMRCA2 is the last time when we are going to buy a foreign jet that is why the most important factor in this deal will be the extent of tech transfer since it is the last chance for us to get advance technology for fighter development which French no matter what they claim will never provide us but Russia will surely do because it is desparate for a big defence deal given its poor economy and wide ranging western sanctions.
Rafale is studied not to require to come back in warehouse to be maintain. If you have the right stock of spare parts, the availaibility may be near 100% (as the Rafale M when on the french carrier).