I think a lot of people double dipped on the PS2 and DS when better versions hit the market. Nintendo is making it pretty hard to choose a Switch Lite over the standard Switch and even harder to own two systems based on crazy decisions like tying certain saves to a single system.
A sleeker model would boost sales into that territory but I don't see one on the horizon based on the news I've seen so far.
Also PS2 (along with PS1) had lots of hardware issues, there were plenty of people who had to buy second or even third PS2's because they broke easily. Not to mention the fact that lots of people bought PS2 simply to use as a dvd player because it was actually a cheap dvd player back then. Switch has neither of those things to help drive extra sales.
Switch will get some of the buying new versions or buying multiple versions (like a family that has OG and then a Lite for kids), but it will definitely be less pronounced since Switch is more expensive than previous handhelds so people aren't just gonna be buying multiple Switches just cuz. When a premium Switch comes out I could see a lot of Switch owners from like 2017/2018 upgrading (I might) but yeah in general Switch doesn't have the buy multiple versions thing going for it as well as DS because it is more expensive and doesn't have the system breaking hardware issues or the DVD reason that PS2 had to expand sales. That makes it very hard for any system to reach those 150-something numbers those two systems hit.