I'm sorry for coming across as a dick, but the idea that you "wasted" time learning a framework that became obsolete is silly to me, and it seems to be a common sentiment.
Ask yourself: at the time you used prototype.js, did it save time on the project?
If you answered Yes, then it was never a waste of time. Knowing prototype.js AND jQuery makes you a better developer: you learned the hard way that abusing prototypes can lead to hard-to-understand code. That can only be a good thing!
No, you're not being a dick. You're right — it definitely made me a better developer. To my memory I didn't switch because of a particular lack of a feature or features, but because jquery was being maintained more consistently.
Community support makes such a big difference, and now that I'm further down the line I'm averse to having to basically make a bet up front.
Ask yourself: at the time you used prototype.js, did it save time on the project?
If you answered Yes, then it was never a waste of time. Knowing prototype.js AND jQuery makes you a better developer: you learned the hard way that abusing prototypes can lead to hard-to-understand code. That can only be a good thing!