I know GoT is fantasy but is it realistic to...

What I noticed over the years is that when a TV show gets popular they start to lace it with political narratives, even it did not in the beginning, sometimes so much of it causes it to fail.

Many people believe profitability is the prime driver of what private media does, more often than not I have doubts about that.

Queen Elizabeth 1st was arguably the greatest monarch England ever had but I take your point that there are far too many women in high status or consequential positions in shows. But women are roughly half the viewing audience so it's prudent to cater for them.

Actually, the show made it all plausible. The cultures of Westeros and Essos were all patriarchal to a greater or lesser degree, and when the show started men were ruling pretty much everything, as was considered right and proper. But after years of the War of Five Kings and then Two Queens, most of the male leaders were killed, and so were their male heirs and brothers and cousins, and in house after house and kingdom after kingdom, some woman was the only person left who could take charge, so she did. Neither Cersei nor Danerys became a Queen until their husbands, sons, and all their male relatives were dead, or had taken vows of some Brotherhood, or were considered ineligible to inherit due to some disability, and it was the same everywhere after years of constant war.

To a lesser degree, the same thing happened in the real-life War of the Roses, where all the major male players in the houses of York and Lancaster killed each other off. After 30-odd years of warfare there were only a few major contenders for the crown left alive, and even after a nobody named Henry Tudor became king, he kept killing seditious relatives until there was nobody left to continue the dynasty, except Queen Mary and Queen Elizabeth, neither of whom had children. Neither one would have become the monarch, if there had been any living male relatives anywhere near the line of succession. But there weren't, there were Mary, Elizabeth, and the odd Jane Grey or Margaret Pole, both of whom got the axe.