The diversity of replies just shows everyone's soil is different and there are a wealth of tactics at your disposal to get your veg grown
I do a fair bit of digging as my soil is heavy. I have also tried old fashioned methods like trench composting - effectively a giant bean trench you dig and cover row by row. Squash and courgettes love this as well as beans
I use surface mulches as well, but even with a fairly extensive compost bin empire, there is no way I could make enough for the whole plot either.
Clay loves organic matter, so however I get it in there, its all good