Threads like these always boil down to some simple points.
1. Do math. If you aren't good at math, hire someone else to do math. It's not rocket surgery to figure out whether you are making a profit, how much, and whether eBay or any other venue, online or off, is a good choice for you. In spite of the simplicity of doing math or getting someone else to do it for you, a truly astonishing number of sellers haven't done it or did it once and haven't kept up on it, and have no real clue what their profit margin might be, or any way of identifying when it starts to slide so they can analyze why.
2. eBay is not your Mommy. eBay, like you or me, is in it for themselves. They don't care about my cat's need for the good cat food, or that my younger daughter is still in braces, or that we had to take the car to the repair guy yesterday. They care about their bottom line and the unwashed mob called "shareholders" reaction to that bottom line.
3. Just because eBay isn't your Mommy doesn't make them the Evil Villain. Few of us, when we set our prices to sell items, care about our customers cats' need for the good cat food, or that their younger daughters are still in braces, or that they had to take the car to the repair guy yesterday. Indeed, when our customers try to get us to lower our prices by telling us of their financial problems, we come here and mock them. If we start to see sales drop off, we alter things and lower our prices to entice customers back. If we see sales rocketing, we raise our prices. Yeah. Kinda like eBay.