The last time I checked, the PS4 is up YTD (according to gaf) from a pretty good 2016. It's doing amazing, we're just used to it.
Is it really? Even at its best, it's beating the PS3's best by only 15-20%, and the PS3 was a third place console for a long time with some really stiff competition while the PS4 took a huge lead and never looked back and came against a Microsoft that crippled themselves out the gate and the biggest console flop Nintendo ever made, all the while the industry and market has grown year after year. With all these factors in mind, it's not doing amazingly, not even close. If I beat a sleeping man in a wheelchair and a limp person with crutches in a foot race, that doesn't make a great runner...