I think I still would play it, I have every pack so far and even if I got most in bundles or on sale, its a good amount of money I have spent on it. And I am not willing to pay all that again just for sims 5...
They try to improve and I feel that things are better after the big patch in december, and I still believe it will become better in the future. And the latest survey gives me hopes for a better personality and memories etc.
I play a lot of older games and I don't mind it. World of warcraft for example, I played for 13 years. I stopped because I just dont feel like an mmorpg person anymore. Or Rainbow Six Siege, it's in it's 5th year now and still new content us coming and events. I still enjoy playing it like on its first day and I wish for many years to come.
I think nowadays it's more common for a company to keep up with the games they made, it's so easy to fix bugs now (rememver Sims 1 or 2, you had to wait for fixes until you bought the newest expansion).
Also, having an older game makes it more likely that you still can play it on your potato PC even after years. WoW i played for 8 years on the same PC and it still worked. Low graphics and lags included and of course the companies at some point have to overhaul some graphics, but its more likely you still can play.
New games tend to look more fancy and not every PC might catch up with that, so yeah. Just my opinion^^