i think one of the key differences is that luton were/are never a big fish in a small pond
to answer your question, style.
If the style is good enough, the results will follow
We'd all love to keep a manager long term and have some proper stability. That doesn't mean we should just give that to anyone though, they have to be the right fit for our club.
Weather you spend it on wages or transfer fees, it's still from the same pot.
Just because you spend more on a transfer, doesn't automatically mean they are a better signing.