I think the OP is talking about gear innovations in the industry not necessarily about him buying gear, could be wrong but here's both.
In any case, I purchased gear before completing training but as I was in a university that teaches technical style diving at the OW level, I bought gear appropriate for that. FWIW I still have all of it years later for my singles setup.
If I read your post correctly, the answer is gear preceded training. Most gear was around long before the training caught up to it, and most training does not specify gear because it is changing constantly. Hard backplates started as a cut up stop sign, BCD's were around years before they became standardized in training *though they actually started as milk jugs, but that's another history lesson*. Very few true meaningful innovations have come about, most of them are variations on a theme or slight improvements.
The Poseidon Cyklon was the first single hose regulator with demand valve at the mouth *the standard for almost all modern regs,until last year it was the only, but the Kraken is now out* and it was invented in 1958, it is still in production today. Oceanic Omega and Hollis 500SE are based very closely on the original design of the Cyklon and are brand new regs. Don't know dates on the lever style second stage but it's been around for quite a while. Aside from balancing mechanisms, adjustment knobs, and making the housing reversible, the regulators are all about the same as they have been for years.
Scubapro invented the stab jacket as most people know it in 1971, they are still basically the same as they were 40 years ago. Some gimmics added, but that's it. DiveRite has claim to fame for the first dedicated twinset wing in the mid 80's, but even that was just an adaptation on the single tank wings that had been out for a while. Oxycheq had the first production backplate thanks to Scott Koplin IIRC and that preceded training standards requiring them by years.
Nothing else is really "required" for training that has come out. Even in cave diving the "cookies" and "line arrows" that are used by mostly everyone are only referred to as directional and non-direction line markers.
The biggest one recently is sidemount. There is still no industry standard for sidemount equipment and there likely never will be. The gear was out decades before the training, and optimized almost a full decade before. Any major gear innovations take years of trial and real world use before the agencies will adopt it.