Yep older riders are hugely at risk when returning to the bike world.
It's not just rusty skills but the roads are far busier and the bikes are hugely different.
100 HP in the 80's was a superbike.
A old CB750 was 70hp, came with a hinge in the middle and part time brakes. And we road them to suit.
I used to have a 1975 CB 750 F1.
Now a modern bike, even a "slow" BMW twin is 120hp and only 220 kg wet and has brakes and handling light years ahead of anything the old rider has experienced.
A fast one is 180hp and less than 180kg, ie over 1:1 power ratio not the old 4:1 of the Rhonda the Honda.
You can even get a BMW that is too light to race and must add ballast to make 165kg to compete.
If you see a bike wreckers you will notice quite a lot of new hyperbikes with a dent in the top of the tank and broken screen. How? The silly bugger does a wheelie and flips the bike at speed- they rarely survive.
A hyperbike can mono in most gears purely from more throttle. Many new bikes actually restrict full power in the lower gears to stop it flipping. The old Rhonda in a dream monoed in 1st, and only got the wheel up a little, not vertical.
Mind you, a lot of the dead old riders are on cruisers ie. Harleys which come with bugger all cornering ability nor brakes.
They are very easy to approach a corner too quickly and run wide as they run out of clearance and scrape.
Another factor is dickheads who ride in close formations this means they can't easily see the proper corner line nor be on the correct position.
Also they are too close to each other for even one to swerve around a pothole, hence they bring down the other riders with them. This is quite common and stupid in the extreme.
In the USA such rides killed over 6 riders purely from one swerving.
A recent one here killed one and disabled three riders.
Maybe a compulsory rider course for anyone who registers a bike after not owing one for five years would be a good idea.
For most returning riders it's like flying a Drifter years ago and jumping into a Turboprop with no training requirements or currency.
I've road ridden for 38 years but know when I am rusty and practice my skills. Most forget anyone can ride fast in a strait line, but real skills are practicing very slow tight laps around witches cones- that generates real balance and control skills. If you can't do a very tight 180 turnaround in a car length, you need to improve your skills.
Those skills are bike irrelevant, even a full dress Harley can do it if you have proper riding skills.