Everyone is either doing OK, or seems to be getting there...but at this point, I'm thinking that's just a temporary thing.
It's like having kids that are super accident prone, isn't it? Just plan on spending time at the ER...
^^This-----to a point
I am 65 and have owned my own horses, non-stop, since I was 12.
I took my first set of Keeper Horses to ages 27 & 29 with nothing more than some stitches on the feisty Arab/Saddlebred and worry about gelding the Arab/Morgan when I bought him at age 17.
These two spent 85% of their lives "before coggins", GMO feeds and in an Era when the family farm dog MIGHT get hauled to the vet for a rabies shot.
Thennnn along comes my second set of Keeper Horses in the early 80's.
Sweet Itch? What's that? Club Hoof - Huh? Environmental allergies - horses get THOSE? Food alleries - horses have those TOO?!?!
Fast forward to 2007 and my heart horse (in the avatar) is diagnosed with "Equine Metabolic Syndrome" WHAT?! What the HEdoublehockeysticks is THAT?
June, 2010 another of my TWH's is diagnosed as being insulin resistant - whellll, I already KNEW what that was thanks to the EMS horse.
There's plenty more but I'll stop there. Suffice it so say:
Since May, 2007 I can truthfully say I have spent more in vet bills, allergy stuff, stuff for metabolic issues and ancillaries than ever spent in my entire life of horse ownership.
So yes, it's a sign of many things:
1. More horse owners that really don't fully understand how to work their horses to prevent injuries.
2. Weaker breeding (in all breeds) because breeders are breeding "for that big win", with no thought to good conformation, good mental health, good physical health in general.
3. We live in a much more polluted world than when I was growing up - we will never know the true effect that has had on the gene pool of horses. Mine have been on city water since 1998 - I have no idea if those chemicals might be responsible for some of their issues.
4. Then there's the feed and hay horses eat. It is grown with the same GMO seeds used to produce feed & hay for cattle - cattle that need to grow up and fatten up quickly so their body parts can be handsomely arranged in the meat counter at the local grocery.
And don't forget about "The Other Meat" - lol
So there's one Old-Time-Long-Time-Horse-Owner's theory on your question
I hope it doesn't make you sell your horse but just know that, in this day and age, you need a lot more money to keep a horse healthy than you did, just 15 short years ago