I really don’t know much about this. Why does it take 15-30 years for those sentenced to death to face it?
Why?
Lawyers
The death penalty is lawyer welfare
Appeal. Appeal. Appeal. Then there's multiple issues in each appeal that needs to be waded through. Sure, after 41+ years, you'd think they'd have used up their delay tactics. Inmates can file complaints on their own without lawyers. They have nothing to do all day long so many get their jollies filing complaint after complaint after complaint.
Another reason is limited supplies of the injection drugs. There's an abundant supply of ropes, ammo and electricity but some states only allow injections. There doesn't seem to be a limited supply of drugs to put down animals though.