When Trump begins to buy very much TV airtime, that’s a signal he’s beginning to bottom-out.
My hope is that he never spends his money on worthless TV ads and does not begin robo-calling.
And even if he did plan to spend, if I was his adviser, I'd tell him to wait until the very last moment, hopefully after he has the nomination.
At a later point in time, a few tv ads will be necessary. Its no big deal. But I do agree with you that if tv ads became his primary focus, then Donald is done.