Stephen tried to blindside JT. He broached the subject cautiously with Taj, but she didn’t seem to go for it. That was Stephen’s best shot of winning, and in hindsight, Taj’s best shot, too.
It didn’t end up mattering because JT won the challenge immediately following that conversation (the spider web slash puzzle challenge). If JT had lost I have no doubt Stephen would have pushed hard with Taj and Erinn to vote him out. He basically had to if he wanted any hope of winning. I think Taj and Erinn would have gone for it.
Thinking back, I think Steve’s biggest problem was trying to win over the ENTIRE jury. The only way he could win was to highlight his differences from JT, and his only difference was Coach. Half the jury hates Coach. His best chance was to just give up Coach’s vote and explain to everyone that he never followed the “take the strongest” strategy and he only used the warrior alliance to save himself.
JT won 3 immunity challenges in a row at final 5, final 4, and final 3. He would have been in high danger of being voted out for at least the final three and final four tribals, and possibly the fifth as well.
Taking him out at 3 would have been an obvious thing to do. Taking him out at 4 would have still left Stephen and Taj a strong alliance, so they would have only needed to win the final immunity against Erinn. Taking him out at final 5 would have been a bit dangerous, as there might have been an unlikely but possible Coach and Erinn alliance against Stephen and Taj. None of those were ever an option because of the immunity though, and taking him out at 6 would have been very dangerous.
Didn’t Stephen once talk with JT about Tyson being a possible threat for an immunity run, and maybe JT could be that person this year instead. It’s a bit ironic to look back at that comment now. 
This is a really savvy analysis – I think you’re absolutely right about this. What a rascal!