In his defence, (and I think Shilton is overrated) he probably didn’t think he needed to bother jumping. Because he wasn’t factoring in his extended arm into the calculation for catching the ball.
The win at all costs, even if it means blatant cheating is something I struggle with. To even consider handballing at that point in the game puts you in the top 1% of cheaters.
It's not my cup of tea either, but I think there's very much a tradition in some parts of the world of "playing the ref"/being "clever". Getting away with what you can is thought of as part of the game, and a skill when done well. At the worst it's considered a bit cheeky, but possibly endearingly so (at least if it's your team).
In contrast, British football deified
The Reducer, preferably
Early Doors, just to
Let Them Know You're There. There have also been plenty of good old fashioned honest dark-arts on these Isles - like treading on the defender's toes when you're backing towards the goal, off the ball, elbowing your opponent in the chest in close situations (corners) etc. All of this was again a question of what you could get away with without getting caught/drawing a booking (hence why you get the reducer in early, when the ref doesn't want to get his cards out yet).
I've always found it interesting how going in recklessly hard in a way that's designed to intimidate and potentially injure an opposition player, and doing it early so as not to get booked, isn't as despised as using your hand to control the ball into the net.
EDIT: One day I'll have to go and watch the famous Ireland France match where Thierry Henry's handball led to a goal and stopped Ireland qualifying for the word cup. Because I wonder how many times he was intentionally kicked, tripped, held, or shirt-pulled in it.