Once upon a time we retained some aircraft whilst a new one was introduced. The Vulcan wound down as the GR 1 wound up. Lightning’s and Phantoms overlapped the F3.
As a result newly introduced aircraft had time to reach full operational capability. The arb scrapping of the Harrier combined with the premature demise of the GR 4 means the F35 is forced to run before walking.
its little surprise they do not have the resources to generate a display aircraft. I for one would rather the display pilot that is eventually selected has a decent number of hours on type and completes the work up program as outlined by previous posters.
I have no no idea what gate heights would be used on an F35 but suspect they may be different to a Typhoon, Jaguar or GR4.