Then again, I think there will still be an abundance of parts for Myvi like old Saga, Wira and Satria even though it becomes obsolete. So many K3-VE Myvi going around and there are also a lot of 1.5 litre 3SZ-VE users which also includes Avanza 1.5 and Alza...Oh most definitely.
But overall maintenance cost the Proton will be expensive now because it's a new car and Myvi is more established. But give it a few years and Iriz just might be the same. Then again given a few more years the Myvi will be obsolete.