Missing Tomatoes

The tomato plants have continued to grow and are now too tall for me to reach - I will need a ladder to pick them. Of course, based on what they have produced, that may not be an issue. I've gotten a few good-sized cucumbers, but only a couple cherry tomatoes. It seems that all of their effort is going into height. The plants are flowering, but most of the flowers are falling off without producing fruit. Any ideas?