Ranked makes no sense

When I played my Placement games this year I got Bronze 4, last year was Silver 3. I went 56-86-114 27 towers taken 186 wards placed and 25 PINKS while winning 5 out of 10 games. This was when the dynamic Q was disabled so I played on the old Ranked of " MID OR FEED" "I WANTED TOP SWITCH OR AFK" so that was good to play on.
My friend have not played ranked in over a year was Silver 5 during season 4 and Went 27-77-77 with 9 towers taken 61 wards placed and 16 pinks, while only winning 2 games out of 10 and got placed SILVER 3.

Is it the KDA that get your tier up/ TOWERS/ WARDS/ PINKS/ GAMES WON 5.6-8.6-11.4 ME 2.7-7.7-7.7 FRIEND 8.34 ME 2.7 FRIEND

TOWERS ME 27 2.7 PER GAME FRIEND 9 0.9 PER GAME WARDS ME 186 18.6 PER GAME FRIEND 61 6.1 PER GAME PINKS 25 2.5 PER GAME FRIEND 16 1.6 PER GAME GAMES WON 5 OUT OF 10 FRIEND 2 OUT OF 10

So Winning games doesn't matter So wards makes no difference So towers and objectives have no point So KDA is just for show So PINKS have no point