I beg to disagree on that point. About a month after I got my Vado 4.0 in 2020, they announced the SL series and, for me at least, it obsoleted the bike I'd just bought and I've been waiting two years to justify replacing it. Then of course my new SL has the new Mastermind TCU and OTA updates vs the original generation, and for some people the automatic shifter available in the big Vados is a game changer. And that's just in the Specialized range.
In the future, if nothing else, developments in battery technology will lead to batteries that carry more charge with lighter weight and who knows what. From my standpoint, I wish that development would slow down since I have a habit if "having to have" the latest technology and changing e-bikes is a bit more expensive than getting a new smartphone!