Don't feel bad, my nephew loves trains and has a huge collection. I know he'd love the trainbots but between his age and their price, I know that's not a good idea at all. I have the original MP Optimus I got in a clearance bin, MP Grimlock, and Ghostbusters Op. Those are plenty for me, I even skipped Thundercracker, as a friend gave me the great Classics-mold one AND the Legends size CW one, and I later got the voyager 2-pack. Between all those, I don't think I made a mistake skipping something where I could see in Toys R Us looking through the plastic, that many thin plastic parts rotated on plastic struts the thickness of toothpicks, and more recent MP versions have gotten worse...
As far as the collecting trends in general, I'm rapidly being priced out of a lot. And not just Transformers. I posted a 'protest pic' of MP Grimlock on my Godzilla shelf, because the mechagodzilla I wanted wound up over $300. I can't do that right now. Mecha-King Ghidorah, same story. I had a computer blow and I needed that more. I sold most of my TFSS stuff, all my Alternators, etc when I last had to have a tumor out. There's nothing wrong with admitting you just can't waste the funds, it's healthier to admit it BEFORE you actually NEED to.