It's sad when you've been with a company for so long and you see the issues and can do little to help correct them. I've had 5 full time jobs in my adult life. One, the first, was only 6 weeks because I was not given what was promised. I've been fortunate to be able to have had my own side business for about 15 of those years. My tenures are not as long as yours, 6 weeks, 2.5 years, 5 years, 12 years and 18 years in the current company. During this time my roles have changed dramatically too. From a tech building PC's and networks to managing DR, office construction projects around the country to basically anything no one else wants to do. If it's hitting the fan I get the call to manage the issue to resolution. It's kept the career challenging enough to keep me interested.
As far as retiring, I tell everyone I'll retire at noon the day they bury me. Part of that is choice, part is not but hopefully can change that before the time comes.