ZD,
It’s not harder to get non kitniyos in Israel than in US. However, there are many additional products for pesach that are ktniyos.
The other issue with kitniyos is that they were grown near grain crops and that the individual items would sometimes get mixed up.
That applies to quinoa to some extent as I understand, it does not apply to potatoes.
So as far as quinoa, ask your CLOR.
As far as saying the minhag should be abolished, the people who wish so, want to do so just to show that they can overturn a centuries old hangagah at their whom and not for any neccesity. There does not seem to be any pressing society need to change the minhag. There are way more options today for food than there ever has been.
Thank you, thank you for your wording and tone. Thank you.