Random botched burglary is not even possible in my view. A common burglar isn't escalating an unforeseen botching by adding the logistical nightmare of lugging and loading up a 84 year old mobility challenged woman in whatever car he happened to drive. He's leaving her there, dead or alive, and taking his chances.
She was clearly targeted for kidnapping in my view. And targeted for either ransom or to punish someone. No other realistic reasons to take her with you. I mean, yeah, there can be outliers and people can conjure up all sorts of fantastical reasons a perp might choose to bring her along, but I'm going with the most likely and saying it was ransom or to punish. And every day that goes by without her return, the latter is looking more and more like the true motive to me. And I don't like that I just wrote that.
JMO.