Keeping North and Germain in power, yes that can be firmly placed at George III's feet, but the rest was pretty normal for monarchs of the era.
But I seem to remember that Lord North was the only guy that could command support from both the House of Commons and the King for an extended period of time.
Just look at the ministerial instability of the 1760s, and recall Lord North's tenure. Lord North has something that all the other PMs in the 1760s failed to do. He established a secure, stable administration.
Something that Grenville, Chatham, Bute, Rockingham, Grafton failed to do.
And he was congenial to all people who matter, something that is not true to any of the above
I will quote J Steven Watson in The Oxford History of England:
"Lord North believed in gov't more than in his own ideas. He was therefore acceptable to the king. He had no intention of forcing any new policy on the commons. He too believed that sleeping dogs should be left alone. he was therefore acceptable to the ordinary member of parliament. He believed in conciliating as many leaders of importance as possible. He was therefore acceptable to any politicians except those who demanded the first places for themselves. In foreign affairs he believed in non-intervention in Europe and a firm but quiet colonial policy..."
And also.
"Between 1770 and 1774 Lord North successfully reestablished a stable administration, not on the king's influence so much as on his own tact. He had ha advantage over every first lord of the treasury since Grenville in that he was in the house of Commons himself..."
Basically North was an excellent leader of peace times, he was even popular before 1775. He repealed most of the Townshend Acts except that of the one on tea, and between 1770 and 1774 was the most calm period of relations between the colonies and the mother country. The East India Act was something that he didn't forsee, as he simply thought that the Americans won't object to paying for Tea from the East India Company as long as it was far cheaper than smuggled tea. He obviously miscalculated.
As a war leader, he was inadequate. Even North himself thought he was inadequate.
"Lord North felt as vividly as anyone how inadequate he was as a war-minister: he begged to be allowed to resign. The king, seeing no other man who could hold together a cabinet to prosecute the war, answered his lamentations with appeals to his loyalty and courage. It was difficult, certainly, to find a possible successor within the cabinet, while a look at the opposition showed nothing but feuds."
Basically, North was kept for lack of a better alternative. Remember, Chatham was sick, his son was still too young, Fox was not yet ready, etc...
His success in 1770-1774 and the memory of the instability of the 1760s kept him in office until 1782.