How many people using 'jpeg' productively to create every day applications do you think understand the DCT?
But there is actually one more problematic area for jpeg: encoding of graphs, drawings etc. with a limited color palette and straight lines. Here, jpeg artifacts become more visible, and to reduce them, you can either turn up the quality, or use a better approach like svg or png. For this, at least a bit of more technical knowledge is required. How many non tech-savy people do even know about svg or png?
But an even more appropriate comparison with ML would be to ask how to improve jpeg to better deal with straight lines. For this, you clearly need to understand the maths.