My older 720p Panny plasmas worked perfectly out of the box. I've never touched the picture settings on them. They range in size from 42" to 58".
My three 1080p Panny plasmas are another story. Horrible PQ at first and had to change settings. After a month or so of use on each I went back to the default settings and get really good PQ.
No calibration needed, I tried several methods and went back to doing it myself. Being told "you'll get used to the picture in about six weeks after calibration" put me off more than a little bit.
There are tests and measurements that are used everyday. Audio systems, video systems, automotive repairs, rocket science, etc...
We as a society do this in order to have a functional product that does what we need it to do.
When it comes to audio & video systems, these tests/measurements and adjustment ensure that the system is reproducing the source content accurately.
Unfortunately there are people that wear rose-coloured glasses that care not for accuracy of their system. Indeed, they want the system to sound and look the way they want, much like an artist would paint a sky with a different color.
You sir wear rose-coloured glasses, as apparent for your love of the default settings (which are known to be horribly inaccurate). There are presets you can choose in the menu that will get you close to an accurate picture (THX or Custom on Panasonic) but you prefer the default (Vivid on Panasonic).
This is all well and good for you. But please don't try and put your rose-coloured glasses on someone else that might be trying to have a 'proper' setup.