These same flaws exist in every safety device we deploy. In practice it's obvious that having a consistently deployed base mostly solves these issues. There are corner cases, to be sure, but how is the greatest amount of good served?

Having these on delivery trucks ferried by unskilled drivers in non emergency vehicles who might just happen to be close enough?

Or just having them in almost every house on the block even if some number of them fail to work on first use?

I strongly suspect the latter is the better choice. Just replace AED with fire extinguisher and we could literally repeat this entire conversation.