Holyoke Mayor Alex Morse has closed to within 5 points of Rep. Richard Neal despite an unprecedented smear campaign by the state Democratic party.
If Morse wins that would make four successful primary challenges to longtime Democratic incumbents.
That probably doesn't sound impressive, but let's remember that incumbents generally win reelection at least 85% of the time.
And when it comes to primaries, incumbents almost never lose, winning over 98% of the time on average. However this year is different.

The eight current members of the House who have been felled in primaries and district conventions — five Republicans and three Democrats — is already twice the number who were defeated in the 2018 election cycle, as ideological and generational battles roil both parties. The last time eight House incumbents lost renomination outside a redistricting year was the Watergate-era 1974 primary season.

If Neal loses that would make 9 incumbents losing, which would be the most in a non-redistricting year since Nixon was secretly bombing Cambodia.
You would never know that we are seeing a once in a lifetime populist revolt going on. You wouldn't know it from the MSM, or even from most left-wing sites.
No one thinks that change is happening anywhere close to fast enough...and they are correct.
However, just because change is happening too slowly doesn't change the fact that it would be idiotic to ignore what's going on.

Not only are incumbent Democrats getting knocked off at an unusual level historically, the left wing groups that are pulling off these upsets are getting both more hits and hitting a higher average.
538 looked into this (538 is not sympathetic to the left-wing), but they were forced to admit that progressive are starting to get a handle on this.

But in the 17 primaries where progressives (candidates endorsed by at least one of these six entities) went up against an incumbent, the progressive-backed candidate lost 14 times. (Newman, Bowman and Bush were the only exceptions.)

That sounds bad, but here's the other side of the story.

In primaries where there wasn’t an incumbent on the ballot, progressives did better: 22 wins (including Mondaire Jones in New York and Kara Eastman in Nebraska) to 10 losses (including Charles Booker in Kentucky). That’s a 69 percent win rate.

Wahoo! 22 wins, at a 69% win rate, will get sh8t done!
Knocking off three or four incumbents is just gravy when you are DOMINATING open primaries.

While no one is talking about it, no politician, no reporter, no one, you know that the party establishment is very aware of this fact.
It goes a long ways toward explaining why they are shitting on progressives so publicly. They have to discourage progressives or this could get out of control very quickly.

Judging by what I see online, the establishment's strategy is working, because I see far more progressives ready to give up (just as all this hard work is starting to gather momentum) than to keep fighting the establishment.