I have regular spoons but I eat yogurt directly out of the 2.5 lb (or larger) containers. Larger containers have less waste than those single serving yogurts. A spatula could work but I feel that it's still going to be hard to get the corners.
For chips, the freaking' frito/lays dips in those glass jars that are sold right beside the chips are the worst.
Dang costs. I will take the higher costs for large flat containers! Who's with me?!
Like ice cream... no real problem there. Why does ice cream get a pass? It's so easy to get to the bottom.
Yes, I get yogurt in the larger containers too, but have never had a problem with a large spoon being too short.
I don't eat chip dip in general, so I'm unfamiliar with these dip jars you speak of, but they sound similar to salsa jars, and if so, I would never dip straight into them. I'm big on not contaminating jars of food.
It sounds like part of the issue is that you're trying to use storage jars as serving vessels, and yeah, that's suboptimal.
As for spatulas, many of them come with 90 degree angles specifically for corners, that's exactly what they're designed for.
I go through a lot of tahini, which comes in very deep jars and spatulas always work to get out the max amount of product.
Ice cream doesn't get a pass, it's packed in cardboard often, so different economics to the packaging, and it isn't a liquid, it's filled with air so it has to be packed into containers, it can't be poured or squeezed into containers otherwise the air in it would collapse and the texture would be off.
Different physical properties so different packaging.