Broadcast signal strength is only of concern to the minority of viewers who don’t have cable/satellite service. And getting a better antenna will usually solve the problem.
No, many of us use broadcast for the HD quality, not because we don't have a subscription service (I do). In my area most of the broadcast stations have maintained high HD quality.
Wrong. I have the largest antenna I can put up and it does fantastic pulling in analog stations from over a hundred miles away, but it can barely pick up the digital signal from stations 20 miles away. The point is that there is no antenna upgrade that is going to give you signals as strong as analog is right now.