If an existing customer never deactivated their Sony, Hughes, RCA, Phillips, TiVo, etc receivers, they can still use them as long as they are the post 2002/2003 models that are APG compatible, they just won't have access to any MPEG4 or HD channels, VOD or interactive features. The MPG guide stream used by the oldest receivers was shutdown back in 2013, affected customers were contacted well in advanced and given the option to upgrade to a D1x or R1x receiver at no additonal cost. Now, they won't activate any MPEG2 only receivers, including the D1x, R1x and H1x models, I forget exactly when the cutoff was, probably when they dropped the MPEG2 locals from most markets, but up until a few years ago you could still activate one of those models.
D* probably would have kept Sunday Ticket if the NFL would have agreed to renew the rights at a rate that let them offer it at those old price points. Instead it went to the highest bidder Google, so YouTube's non-promotional pricing for Sunday Ticket is higher than it ever was under DIRECTV. DIRECTV's regular price for the final years of Sunday Ticket was $293.94/yr or $395.94/yr if you also wanted Red Zone and Fantasy Zone, while new customers usually got it for free, and if your account was in good standing, it was common for existing customers to get it at a deep discount. YouTube's Sunday Ticket for returning customers is $378/yr with a YTTV subscription that starts at $64.99/mo or $480/yr standalone, for new customers it's $240/yr. If you want Red Zone that's another $54.95/yr.
And its value has only gotten worse if you're a fan of a team that frequently gets picked for the late game of the week, which is no longer restricted to AFC for CBS or NFC for FOX, or the expanding list of national and international games that require additional streaming services if you don't live in the DMA of the teams playing, along with more networks having flex rights later in the season. DTV also offered a PPV option which ended up being cheaper if you only needed Sunday Ticket 1-3 weeks a year to see your favorite team.