The long and short of your story is that yes it is completely related to self esteem - in fact, it is a factor of attainability, which is what the whole self esteem thing comes down to.
There actually WAS a spark for her - you just didn't move fast enough with her, and that's what killed it for you. What you're basically saying is that you liked her, and she liked you. In fact, she liked you a lot! All her signs were indicative of a girl who is super into you - reciprocating passionately, throwing her into your arms, you talking and kissing more, and her even talking about coming to your place. She also texted you two hours after the date,
I'm not sure what you did about any of these things - the clearest thing to me here is that you should have moved fast. You should have gone to your place, to her place, and you should have escalated to sex and had it quickly. On the alternative, you could also set up the next meet as soon as she texted you back - basically she's showing you a LOT of interest, so you have to match her investment and lead to the next step.
But, it sounds like you didn't - and instead she basically backwards rationalized the whole thing as you being much higher value than her, and not available for what she wants - and thus she's going into autorejection and backing out of it because she doesn't want to find that out later. She's knows you're higher value than her, and she knows she's not going to get what she really wants from you long term. Rather than find that out later on in the process and get hurt, she's cutting herself from that possibility to protect her self esteem.
So to answer your questions: