Well, all I can say is in 2024
I got a used ST 1300 that was a 2007 model that had two different tires on it: one dated 2010,
and one dated 2011.
I got this bike nearly one year ago November 2024. The rubber did not seem badly cracked, I estimate they had half of their tread life left on them when I got the bike, and I believe the bike was stored indoors it's entire life, but these tires were nonetheless 14 and 13 years old.
What I did: I used them up on the road!
I put several thousand more miles on it and used the rest of their tread life up.
I never felt like they were losing traction on the road except for the obvious circumstances such as riding over tar-filled cracks on hot summer days or crossing over painted lines on the road in the rain.
PERHAPS they wore out at a more rapid rate during the last couple months of my using them then they did during the first couple months but I really attribute that to me getting more comfortable on the bike and being more aggressive in my turning and braking, rather than riding it like a little old lady on her way to church.