I think this is a really significant vote for the future of the PL.
By linking the top clubs spending to the bottom clubs revenue (and therefore ability to spend) the PL is making sure it has to pay attention to the lower third of the table. The only way for City, Chelsea & United to spend more money is to grow Luton's revenue.
It strikes me as a very sensible move to preserve competition, probably the most "fair" thing they've done since abolishing shared ticket revenue in the 70's, although I'm concerned about how much it will exaccerbate the parachute payment problem - the only real way for City/Chelsea/United to grow Luton's revenue is to push for bigger central payments from the PL, which is what the parachute payments are tied to.