No, top pinching is not a normal part of growing tomatoes. And whether you prune or not all depends on whether they are indeterminate or determinate varieties (see the FAQ here) and how you cage or stake your plants.

I've just noticed that most fruit is born about halfway
down

That would be very unusual even for determinate varieties. The most likely explanation I can think of if that is happening to your plants is either (a) they need feeding to continue producing, or (b) they are in containers and have become rootbound.

Otherwise most vatieties will produce fruit throughout the plant from about 8-10" above the soil right up to the top and indeterminate (vining types) will produce fruit as far up the plant as possible - many photos show folks picking fruit from plants that have been staked up to 10-12' tall. We let ours drape back down over the outside of the cages and harvest fruit off 12' long vines. If you pinched off the top than all that production is lost.

If short, bushy plants are what you want then stick with determinates or bush varieties.

Dave

I was brought up in a family that pruned tomatoes to one stem, trained them to a single stake, and planted fairly close together.

I'm 5'2". I was the principal gardener, and even in zone 5A, where we lived at the time, the tomatoes quickly grew taller than I could reach.

It made sense to me that allowing some suckers to grow would result in a shorter, more reachable plant.

I still prune some suckers, because I want to grow too many varieties, and that means growing them fairly close together. I also like to be able to see the interior of the plant so I don't miss ripening fruit -- or hornworms or other problems!

Frankly, the darn tomatoes still grow taller than I am....

My plants also usually have most fruit on the lower part of the plant . I always presumed it was because the heat stopped fruit set after the plants were larger , but it was cool enough when the plants were smaller for fruit set.It is reaching that point now where I live , what signs do you watch for to signal fertilization is needed???
CDGTXS