Can't tell if you are trying to be a dick or if you are actually clueless. I will assume you are being genuine, and try to spell it out for you.
They turned up the rate of autofill because the playerbase has dropped significantly.
Compile the fact that no one wants to play jungle right now.
Now you have less people overall, but even less people in the jungle and support positions. (Support by nature in NA).
So to counter longer queue times, the increase the rate of which you have to play that role or will end up playing that role.
This is normally completely irrelevant for anything below d3. Because you have a massive grouping.
Even at 700,000 people.
Let's say that it's even 1/24th of the player base is on at any given time.
That is 29,166 people per hour.
Of that you will normally play within +/-1% of your skill rating.
For someone in the 20% it won't matter much at all. (Gold)
For someone in the 10% it will start to be noticed but not really affect majority of games.
At the 3% you will feel that in every game (mid plat)
2% you have to be good to even climb now, because what used to 1% problem is now a 2% problem.
1% have fun.
If you are wondering that the old 1% problem was it was.
1 game per month diamond 5 players.
Playing against people in d1/D2 when in low diamond. Massive skill difference.
And you are always on the less LP gains because of 1 game a month players.
But now with a lower player base, all of that is shifted down an additional %. Thus inadvertently affecting all elos until gold.
Gold is a normalized section, that doesn't really affect anything.
Because gold doesn't normally feel the small changes in the game. And silver and bronze don't 100% of the time.
Aka.
Less players, less people playing specific roles = massive queue time spike.
Let's say out of 100 players, 4 are playing support and 5 are playing jungle.
You got 2 games of no auto filled, which is 20 players. So 80% of the community is dealing with auto filled. If you increase queue times for try players. Then you are still the minimum increasing it to 15 minute queue times.
Auto fill saves time. So that they can get "more people playing the game".