So make new friends. Old people are people.
Imagine having been with your spouse for 60 years, your friends 40-80 years (?), your children I guess at least 40 years, having a new friend has nothing to do with this, you will never know them this good and neither will they.
So it's definitely possible!
For me (anecdote), it's only gotten harder as I've become an adult... then married... then harder as a parent... etc.
I see that in my family, aunt, etc they complain they're lonely but I think it's even worse for them to suffer bad or too short relationships. Heart ache.