I too have all but given up on growing summer squash and expecting good results. I still temp fate and plant several of the zucchini and yellow crook neck each spring but they will be dead or dying soon after the first fruit are picked.
Others have recommended growing winter squash varieties in its place since the stems aren't hollow like the summer squash varieties. I got quite a few Acorn squash this past spring and early summer, but even though they have a good taste, they are much different than summer squashes. After the SVB's take my plants I just buy the summer squash at the market for cooking. When in season, they are pretty cheap since they grow so plentiful.
I feel your pain over this. I remember the first time, many years ago, that I found the SVB's in my squash stems and watched them die very quickly soon after.