The problem isn’t the owners talking to the vets, or ordering procedures, that is almost always orchestrated by the trainers.
The problem is the vets doing whatever the trainers want, without the welfare of the horse coming first. This is one of the important points that needs to be addressed if there is going to be change in the industry.
As far as the past vs the present, I agree that some things have improved, when I rode (mid 80’s) there were tracks that basically had no limit to the Bute you could give. That was a scary thing for both horses and riders. There were some nasty treatments like pin firing, excessive blistering, smoking a horses head with Asmador before they ran, internal blistering (stifles, backs) freezing feet with white gas, etc., these things are still done today but a lot less frequently.
What’s replaced this is multiple joint infections, knees, ankles, hocks, coffin bones, stifles, SWT, and a brand new list of medications. All of these are much more humane for the horse, as long as they’re used as needed and not overused to the point of keeping a very sore horse running that shouldn’t be.