There is always room for abuse x_x
I'm guessing the speakers and bulbs have wifi components or something inside them that would eventually obsolete as well, I don't know enough about hardware development and cycles to know how long the older ones "should" be supported for.
Only 5 years for speakers is a bit much to ask though >_<
Yeah, there is wifi in them, as well as other communication stuff I guess. IoT allows for them to make anything obsolete when they want. I'd be pretty annoyed if I paid 500€ for a hub and 1000€ for speakers last year that no longer worked.