Why are salsa jars so hard to open?

Seems like it's not just me getting old and feeble, or at least only that - the interwebs are full of people who struggle to open jars, particularly salsa and pickle jars.
Pretty much everyone has their own workaround for the problem: wear a rubber glove, or a leather glove, or just use a damp dishcloth to allow for a better grip; use a can-opener or a knife to break the vacuum seal at one edge of the lid; run hot water over the metal lid to expand it and make it easier to open; get the body-builder next door to do it; etc. There are also gizmos and gadgets specifically designed to aid with opening jars, although salsa jars are often too wide for some of these (here is a professional model that some peope swear by).
Obviously, jars need to be well sealed for food safety and shelf-life purposes, I understand that. But do they need to be quite so well-sealed, to the extent that normal healthy adults struggle mightily with them?
Well, one has to assume that food manufacturers are not stupid, and that they have put some thought into the trade-off between ease of opening and safety/longevity. Given that most people DO get them open eventually, one way or another, a.d given that we keep buying the stuff because it's so good, they are probably not going to change things any time soon. Cost and taste are overriding factors; actually being able to open the damned thing, not so much. The internet assures me that food manufacturers are aware of the issue, and are constantly working on potential solutions and innovations. But don't hold your breath.
As to why salsa and pickle jars seem to be worse than anything else, part of the problem is the traditional larger size and shape of the jars, which makes a good grip more difficult. But it has also been suggested that salsa and pickles are usually packaged while still hot, which makes the vacuum seal even stronger. That sounds vaguely plausible, but would the same not also apply to jams?