That’s because we’ve been lied about how old they really are.
There’s no way in hell those bones are “millions of years old”.
Refer to the Nodosaur specimen they found almost completely intact with cartilage and skin recently found in Canada I believe.
How possible is it for DNA to survive millions of years?
The Maryland “science guy” would take us out on school field trips a couple times a year.
We were marching through one of the limestone block tunnels built for the C&O Canal in the 1830s, when he stopped, shined his flashlight up at the ceiling of the tunnel and dramatically intoned “Look at those stalactites. They took millions of years to form”.
And from the back of the group, my 10 year old self said “Seriously??”