Huge difference in skill among players similar MMR in low tiers

This is gonna be a bit of a long post, and will probably sound like a rant, but I am curious about how the matchmaking system works now in DotA 2.

So I used to play DotA 2 regularly about 5 years ago. Back then, I calibrated at around 3k mmr, and I would win and lose games in equal measure, and I played against people who I felt were at a similar skill level to where I was.

Recently, I started playing again, and calibrated at 1.7k mmr (no, this isn't a post complaining about being low ranked). People I play ranked games against often do things that I was not doing a couple of years ago, so I think the average player has gotten better, and I probably am at that skill level. However, almost all games are stomps, either win or lose. Out of 20 games, I have felt like only 4 games were good challenging games where everyone was at a similar skill level.

I'll give some examples. When I play hard support, I am warding, dewarding, pulling the camp to the safe lane in order to pull the lane back towards the tower, making sure I am not leeching off the carry's xp. In one game, the support from the opposition was contesting my camp pulls, and also dewarding. The game was fun because we had a bit of a competition, and I started placing observer wards right outside the range of where I thought he would place his sentry ward. I actually did see him go and try to deward and miss my observer ward which was pretty awesome. Then in the next game, I queue as the safe lane carry, and the hard support only used wards once at the beginning of the game, jungled the creeps alone (right clicks) as I saw the creeps from our lane go right by him.

In another game, the safe lane picked ogre magi (last pick) and I was super confused how to play as the support. Basically so many of the games end up in complete stomps, and I can predict who will win the game within the first 10 minutes (sometimes in the drafting phase). Several players are also shown as being something like 15-5 in the last 20 games on their particular hero at the beginning of the game. At times it feels like the average mmr of a team should be 1k higher than the other by the way the teams play.

So, what I'm wondering is, is the same thing happening in the higher brackets? Is it because people are smurfing all the way down in the crusader bracket? Is the matchmaking system broken because there are fewer players now? I don't mind losing, but it's not really fun when only 4 in 20 games are actually fun and challenging.