It is, but after ~7 years of "staying the same" it was just time for me to move on. Maybe I move back again, but for now I see no reason. I won't buy a new licence for stuff I basically already had for years too.
When I discussed this with a friend lately we actually found comparison to a human relationship in it.
LFS is like the girlfriend you got in grammar school. Best fit for you, does what you like, adorable in every way. You commit to it.
Then the years go by, you yourself change a lot, grow up/older, learn new stuff, jobs, people, places - and your girlfriend does not. Yes, some jewellery here and there (CTRA, Leagues), few new clothes from time to time (patches and graphics updates), but apart from that she is exactly the way she was the moment you met her. Waits for you at the same table in the pub whenever you come for a visit. Is always happy to see you, no matter how long ago the last visit was.
You come back home telling stories about all the new things you did and got to know, and she ...is the same. Can't tell stories of her own, has no new experiences, dwells in memories of your first few years. You still like her, but with a lot of pity and desire for her to change after all.
This comparism breaks apart when it comes to "cheating" on LFS with other sims (
), but I hope you catch my drift. I think the same happens with long TV shows. Most shows last under 7 seasons/years, and those that do mostly turn bad after that. Others that steadily develope can go much longer (looking at you Simpsons and Doctor Who).