Is kneading needed?

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It seems most recipes use an autolyse followed by stretch folds, instead of kneading. 

Is kneading not as important when you have long slow fermentation and proofing periods?

Yes to your question, you can get adequate gluten development with long fermentation and a bit of stretch-and-folding,without vigorous kneading.

But I might question your premise.  There are different recipes for different kinds of bread.  Some, like classic baguettes, require pretty vigorous kneading.  Some higher-hydration breads benefit from several minutes in the mixer with a paddle and moderate speed.  A lot of breads want *some* kneading.  There's a bunch of different textures you can aim for, and different combinations of hydration and dough handling to get those textures.  

For all intents and purposes, Stretch and fold is a style of kneading; pulling gluten into strands then tangling them up in some methodical way to create some stucture.

The different methods trade off speed of gluten strand formation vs intended process time, given the desired internal structure.

To get big holes you need to move your dough around less so S&F is intended to pull gluten with minimal interference to the dough, also incorporating extra air. Even scooping your dough from a bowl will tighten all the gluten and close holes. Turning dough from a bowl, if there is any amount of cling to the sides results in a small coil fold and landing on the workbench is a slap, which are both kinds of knead.