Last year, I made a same question as you to a certain person concerned.
He looked at me with a meaningful smile, and he asked me my opinion about the new M.

I wondered about their planning.
Successor may not be welcomed by everybody
because M03s have high versatility, its substitute is very difficult.

But I have heard also that last year M03s were most sold in their nine years history.
So,I think Tamiya will not run a risk.
Their business opportunity seems to continue for the time being.