i don't know where your confusion is coming from, someone asked if people would be happy if morata had a morientes like career with us scoring 12 league goals a season, and i brought up a club legend that has averaged like around 14 goals a season to highlight the fact that it isn't really as bad as it sounds. I further elaborated on how Morata would contribute more than just goals by speaking on his skill set.
rooney has only ever scored 20+ league goals in a season TWICE, he has been at manchester united for 13 years, and from memory, i'm pretty sure he has led the line more than just two seasons. that's besides the point tho, as i already asserted that morata would contribute more than just goals, much like rooney used to.
Like i said regarding your #9 claims, if there's been a shift there it has been to expect them to be more than just goal scorers. Strikers are now expected to create as well as to finish. There's more emphasis on hold up play, movement and passing as well as the ability to play wide for strikers now than there used to be. Benzema leads the line for Real Madrid yet he only scored 11 league goals last year but created 38 chances and assisted 5. Suarez for Barcelona scored 28, assisted a ridiculous 13 and created 62 chances. The pressure on #9 to be the main/only goal outlets has been lessened in recent years with most teams adopting systems with interchangeable attackers, and the rise of "false #9s" and "goal scoring wingers" to prominence, so much so you'd be hard pressed to find teams with classic byline hugging, ball crossing wide players like back in the day.