Well.... not only is your model 6 yrs now, and it was "getting ready" for a year before that, so it really is 7 yr old and lacks some 64-bit firmware under the hood that can't be changed.
I never felt like Lion or later had a compeling use or need in a desktop, and there are cheaper models that can do a lot, but software has always and forever driven the sale of hardware. That was true over 30 yrs ago and still true today. (And hardware will give developers excuses to do things that they could not do before).
Complaints here dont' do anything but there are threads going back of others expressing their displeasure.
And even the Mac Pro 2008 3,1 does not do well with ML and many found that they really had to go back to 10.6.8 to have a stable reliable business system that they could use and depend upon. So the i-ification to me is more cutness and for a different user. Microsoft ruined Windows with its Metro that also has users upset and has little to no place on the desktop.