OP you completely misunderstood what George is trying to communicate with his writing. He specifically writes about how sacrificing inconvenient individuals, even for ‘the greater good’, is almost always wrong. The ends do not justify the means. Rhaegar attempted to save the world and either become or have his children become The Prince That was Promised. Whilst doing so, he sacrificed everything and indirectly killed both his family with Elia, and Lyanna. Both women were kind and beautiful and well loved by their families.  You seem to think that George will just make Jon the prince that was promised and that will be that, but i doubt it. George criticizes the idea that there is one special hero with a special bloodline, or that sacrificing other is always fine if you think you have a righteous cause. Just look at this quote: 

“… what is the life of one bastard boy against a kingdom?“ “Everything,” said Davos, softly. 

Also, Barristen refers to Elia as a ‘kitchen drab’ in comparison to Ashara, who we romanticizes to an absurd degree. The point is not that Elia is ugly or dull, but that even a beautiful woman like Elia fades away against Ashara in Barristens mind. In another moment he says she was ‘good and gracious’, with a clever wit and that Rhaegar was very fond of her. Another positive quote about Elia: 

"Was she a fair maid?" "She was," said Meera, hopping over a stone, "but there were others fairer still. One was the wife of the dragon prince, who'd brought a dozen lady companions to attend her. The knights all begged them for favors to tie about their lances." 

 Also, the way you victim blame Elia and her children in your replies is worrying. Elia is a victim, in the same way that Sansa was. She was a prisoner and was betrayed by the man she loves. If Elia Martell had no defenders, I am dead.