I believe that it's impossible to say how long it's been since the pictured hooves were trimmed, as individual horses have VERY differing growth/wear rates-that said, those hooves have NOT been properly trimmed, no matter how long ago it was! Yes, the heels are ABSOLUTELY 'way too high; however, they probably can NOT be taken down to a proper, proportionate length of heel/toe in a single trim, but should be done over a series of trims, done perhaps every 1-4 weeks, until they are correct-and THEN maintained properly!! I also would be concerned about how 'narrowed' they look....
I see evidence of some stressful occurance in the growth pattern, too-could well be nutritional. Soak them well in mud or just water, before trimming. Caution may be needed when trimming, as often, horses whose proper hoof trimming has been neglected, will have the 'quick' advance into the sole/wall, and must be trimmed only a little at a time-and more frequently, as I mentioned above,to minimize the likelihood of soreness and even drawing blood!