You have two things going on here.

One, you have a moderate case of Fertilizer Starvation. Fertilize twice a year, do you? It's not remotely enough, nowadays, even though yes, that's the way our fathers did it. What grass you have isn't thriving, it's just barely holding on. In MA, you should be able to introduce some KBG into the lawn, but that KBG won't thrive, spread out, unless there is a more regular pattern of fertilizing. If you do start more fertilizing, that KBG will aggressively spread out, and take over from the junk.

Now that you've got weak grass,

Now that you've allowed spaces to develop in that lawn that are not disputed, are not competed for, are not being assaulted by your aggressive healthy KBG (and to a lesser extent, rye and fescue), there is a real opportunity here.

That opportunity will be taken, will be exploited, by the most aggressive, most healthy, most pervasive grass in our (yours and mine) climate zone. Poa Annua. Annual Bluegrass. It looks like heck, it fades fast in summer heat, and it's darned hard to get rid of. It germinates in the fall, rather than germinating in the spring. You have to put down a pre emergent once, perhaps twice, in August and the fall, in hopes of keeping those seeds from germinating, otherwise once they germinate, your pic shows how your lawn will look every Spring. But along with that, you have to make your present 'good' grass stonger, more aggressive, so that there will be fewer areas for the Poa to attack. But all those seed heads you see are Poa seed heads. And this fall, after the annual plant dies, those seed heads are going to germinate. Unless you do something about it.

Good luck with it.

Thanks for the input. I was afraid to fertilize because I thought I was fertilizing the bad stuff. Should I put something down this week?

As for the pre-emergent, that means I can't overseed in the Fall, correct?

Yes, on the fertilizer, and yes, on 'is it darn tough to get some seed sprouted, and growing, which means I can't put down Pre-M when it would do the most good, even though the grass would likely sprout and grow in the areas where the poa died?'

You tend to end up with a multi-year plan. This year, we'll get the KBG growing, recognizing that Pre M isn't happening, and we'll live with the poa next year, but keep the KBG aggressively growing, and spreading, so that when next year's crop of poa dies, the KBG is spreading, and next fall, we'll Pre M, (no seeding, but yes, spreading) and try to stay ahead of it.

It ain't easy.

Good luck with it.