Are Speaker Manufacturers just "optimistic" ?

There already are test centres for BS5839pt8/EN54-24 compliance. So if your Penton or Toa, and you want to certify your speaker as VA compliant (which is mostly physical, i.e. thermal fuse, ceramic connector block, etc) you can, but they also give enough acoustic data to give meaningful EASE type data. So it does exist, but costs a fortune.

When doing VA, generally part of the contract talks about meeting 0.5 or 0.6 or higher RASTI or STI, if the client reckons it sounds crap, you get someone in to test system to get a test measurement, and if you fail, you pay for testing, and doing whatever it takes to meet STI, and subsequent remeasure! So accurate speaker data, in the 100V line VA market is already standard, for EN54 compliant systems.

But, and it is a big but (and I cannot lie...) VA is life critical. And the systems are big and expensive. So BS is not accepted. Sticking a couple of Eons on sticks is not life critical. So the BS that all other manufacturers spout is marketing "re-interpretation" of measurements to help shift boxes.

Thankfully, good manufacturers will balance marketing BS with risk to reputation. Most multi $XXXXX boxes/systems will come with some sort of modelling data, and easy enough to measure result. If the two don't match up, someone pays. At the arse end of the market, what DJ is going to measure his boxes output in any meaningful way, against claim by manufacturers - they will either be loud enough or not. So manufacturers get away with it, especially to those who see big numbers (PMPO, Peak SPL or whatever) and hand over money accordingly.

The problem is, most get away with it, as we don't measure, and we suffer a touch of Emporer's new clothes syndrome.