Two main reasons.
One, I'll be dead soon enough by other causes. I've already outlived a lot of folks I knew. I may not win the race, but I'll put in a respectable showing. I don't believe that immortality is a thing. When my time comes, I won't cry about it. It's not like it's something that is unfair and only strikes a few humans. It gets everybody.
Two, no point in rushing it. I know how bleak life can seem. I've been through some pretty bad depressions where I came close to offing myself. I never want to get that close again. Ever since I stepped away from other people's expectations of me, my outlook on life brightened considerably. My life is my ship and I am the captain of it. FUCK everybody else who dumps their shit on me. There's always something new happening every day, and I find that too goddammed entertaining to miss out on.
I like my favorite foods. I like the smell of fresh air, so I take walks while I still have the ability. I like trading laughs online.
And that's another thing. If you have an internet connection, you don't need to travel. Let someone else spend the money and the effort. Watching their videos is the next best thing to being there. Hell, YouTube even lets you visit other planets!
In my old age, I now have the time to catch up on reading the classics. In fact, everything I gave a pass on in my youth I now have time for.
There's a ton of old anime that I would have had to spend money to see in decades past. Plenty of sites out there that let you watch it for free, now.
Naw, I'm too busy to consider going to my grave, yet. But if it happens, okay. Then I'll find out if there's anything beyond. Not one second sooner.