If you don't understand the differences in how we are 'buying' the F-35, then you won't understand why this is apples and oranges.
We are 'buying' a number of flying hours per year - we are 'contracting for availability' rather than buying the aircraft. It is in effect a lease. It is incredibly complex and I only ever scratched the surface of it, but it is a totally new way of doing business. Compared to the cost of re-working Typhoon into something similar, it is a lot less effort for far more return of investment.