Lets put an old myth to bed. Why did Scoles retire from International duty at 29?

Let's say if Scholes was at 29 and still playing CM would he of retired? no so the reason he did retire is because at that time all 3 (Scholes, Gerrard, Lampard) were on good form and somehow the manager had to play all 3 on the pitch so he shifted him to the left... but the disappointing this was that Scholes just spat his dummy out and didn't even put in a good effort.