without changing any of the remaining blue partys voters’ second choices

That's not true; the whole population shifted left. There are voters in each group whose choices have changed as a result of that shift. If I’m doing the math right:

• 4.7% of voters switched from B>G>R to G>B>R
• 5.3% of voters switched from B>R>G to B>G>R
• 5.2% of voters switched from R>B>G to B>R>G

If all of a sudden the blue party found their numbers slipping then now the pressure would be on them and they would likely hold a little more weight on who they would want their second choice to be

I’m not sure what this means. The voters changed their minds. Some people who originally voted Blue first, Red second have changed to voting Blue first, Green second. The Blue Party leadership can’t change that. Are you talking about the voters or the party?

whether they would rather allow red to gain the majority or throw their support behind green

They did throw their support behind Green. That’s what caused them to lose! This is the fundamental problem with Ranked Choice Voting that I’m illustrating. The way it eliminates candidates makes it behave illogically: The population moving to the left can cause the winner to move to the right. Moving a candidate higher on your ballot can hurt their chances of winning.

but then again if it were we’d have way more parties than we could keep track of, making the path to the majority even more complicated.

Yes, RCV behaves even worse with more candidates, essentially choosing a winner at random, but it becomes hard to follow, so I wanted to illustrate the simplest case concisely.