I'm with you on the environmental front. Sadly this is not how environmentalism works in a capitalist system. When we give up a brand new modem, that plastic/copper/silicon/lithium you and me helped save is not left untapped. It's exploited for other means, such as for building nukes and warheads to ship offshore.
Same with petrol. When we are going to ban petrol/diesel cars in a few years, that fuel is not left untapped. It's reserved for billionaires so they can use it in their rocketships so they can kick of star wars when they've flattened the earth.
Also, using eBay is a choice. I doubt people with OCD will force themselves to buy old goods on ebay. But when they sign up to VM, they cannot choose to recieve a brand new modem.
Furthermore, VM branding their own routers is environmentally unfriendly in my experience. When they gave off-the shelf modems back in 2009, they gave me a D-Link DIR-615 which I have made use of in one way or another for almost 2 decades. An decomissioned VM router has absolutely no use, as a router. It's a router that cant route anymore.