Why is flex placement still broken

I know that I ended season 6 in mid bronze, like most bronze players would say, that's really because i didn't try. I was still practicing champs in normal games and practicing and I didn't even try to reach silver until the season was almost over. However, as soon as I did try to rank up, I gained two ranks in one day and managed to get a 77%-80% winrate on kennen top. Now even before in flex que I feel that I didn't do all that bad in my placement games, but it placed me in bronze 5. In my original placement games I played mechanically difficult champions that I hadn't taken the time to learn. I fed in almost every game and got placed in bronze 3. This is why I mostly didn't care about ranked, I practiced and got better at my champions through normal games, and when i finally wanted to, I found I was capable of ranking up. My point is not that I deserve to be placed really high and all, but at the very minimum I should be placed in high bronze - silver. Is it set up so that you're new rank is influenced by you're old one? Even with the hot fix of an additional placement game for everyone, I was still placed in bronze 5. What pissed me off even more is that by having another placement game, I lost a bit of lp as well towards ranking up. Did the hot fix really fix anything? I saw other posts on the boards about people having the same problem. Higher elo people such as gold-plat players are being placed in bronze - silver. How does this make any sense?