Any reason to keep One SL?

So ERA100 prices are dropping but still the OneSL used-prices are relatively high.

So this gives me the chance to sell my OneSL for nearly the same price as a new ERA100 will cost me. example from Europe: sold a used OneSL for 150€ and currently new ERA100 for 180€ or even 140€ (Sonos-refurbished)

Am I overseeing something here? Is there a reason for OneSL prices being that stable?