There just wasn't an Internet to allow for several months of "shock and horror" from the fandom to circle the planet every day until the film was released.
TMP's were even more shocking. Since Phase II never made it to air and the planned Paramount TV network was scrapped before it could ever launch most fans and casual audience members never saw the TMP set designs, uniforms and props before the first movie's earliest production images were released to the public. Discovery is a radical reimagining of the aesthetics we're familiar with in the general TOS timeframe but Klingons are still gruff, intimidating aliens with cranial ridges and warp speed is still depicted with cool special effects showing a ship zipping along at an incredible velocity. When TMP hit theaters the changes to the Klingons were far more seismic than even Discovery's makeup designs and the look of the 1979-era Enterprise compared to the 1969 television incarnation of the vessel couldn't have been more stark in many respects. With the Discovery we've had almost 38 uninterrupted years of seeing modern ideas about Starfleet ships and alien races on both the small and big screens so the newest series isn't that big a change of pace from what we've been used to over the past three decades. DSC is a very noticeable aesthetic shift. TMP was a revolution and a jump far bigger than any other franchise of this size has ever attempted after a hiatus and change in audience tastes and expectations.
That's not true. TMP didn't have so many Star Trek episodes behind it. Changes in Discovery are simply way of saying - screw the past episodes, we can do better. They are dismissing a thousand episodes of visual style just to fulfill their own wish to create new star trek universe.
I think this is an assumption that a segment of the fanbase are making for themselves. At no point have the show runners said they can 'do better' or been disrespectful to what came before. In fact it's been the opposite. Visual changes are just a reality of Discovery being made in 2017. And if they are creating a new trek universe why is that a bad thing?
Well actually there is two. The prime timeline and the Kelvin timeline. The 741 previous episodes aren't going to magically disappear if a third trek universe was created.
So? There was already an establish look to the Star Trek series, and yet they added more to it, after a ten year gap.
It's basically the Trekdom version of the 'gay agenda'. A nebulous, non-existent conspiracy theory made up by people afraid of change.