The Eruv — Halachic Tool or Glorified Shabbos Loophole?

I have lived in Lakewood over Fifty years, KE”H,raised a family of children, grand children, great grand children, Kain Yirbu.

Every week for the past few years goes up signs regarding not to use Eruvin, the more signs that are posted, more and more people are using the Eiruvs all over town. Carriages, Strollers, bicycles, just about everything.

Many people never realized that there are Eiruvs around Town, till they read all of the signs about not using the Eiruvs.

An eruv is not a kulah from the 1960s. It goes much further back – there are Gemaras that discuss it.
Eruvin 68a brings a story where Abaye was asked why there is no eruv in his town. Many meforshim (Birkei Yosef, Chasam Sofer, Avnei Nezer, and R’ Moshe Feinstein) use this Gemara as proof that there is actually an obligation for a Rav to make an eruv where it is halachically permissible to do so.
I don’t think people today treat them with no awareness.
Where I live, yes, I use the eruv. Do I trust the eruv? Considering that it’s not a person, no. But I do trust the Rabbonim who oversee it!
I don’t personally check the eruv. The local Rabbonim check it every week, and I rely on them.
I’m not sure what chumros of the past you refer to when asking if they were discarded, so I can’t really say.
To say that R’ Moshe was hesitant or opposed to “many” of the eruvin… I’m not sure what you refer to. Do you mean in places like Brooklyn or Manhattan? That is well known, because he felt it was not halachically permissible to make an eruv there. In places where it was permissible, he held (as I wrote above), that it was an obligation to make one. Obviously, it needed a knowledgeable Rav to oversee it, to ensure it was done correctly. But he wasn’t opposed to the idea of an Eruv.
I’ve been told that in Elizabeth, NJ, R’ Pinchas Teitz zt”l built an eruv, but was nervous that people would forget the halachos of carrying on Shabbos. Therefore, one week each year, the eruv was taken down. It was usually done the week after Parshas Zachor – since everyone came to shul to hear Zachor, he’d be able to announce to the entire community that the following week, nobody should carry, as the Eruv would be down.

relax….
go learn the relevant sugyos and come back to us.
also learn some history… like almost every city in europe had an eruv, and many were not on the standard that we build today,
asides we have the cahzon ish….

Until moving to Nassau County when I remarried, I had never lived within an eruv. I still find myself checking pockets on Shabbos.
Gone are the days of house key tie clips as we have push button door locks.
Out of habit I do not carry on Shabbos, but trust the Rabbeinu who supervise the local Eruv and my wife carries.
We live across the street from a park full of families on Shabbos. Many Ashkenazi kids play baseball, the Sephardic Rabbis assured it. Loads of scooters but no bicycles on Shabbos.
I am not yet comfortable with all the baby strollers parked outside shul every Shabbos, but an eruv has greatly increased the female attendance.

There are many things that are different nowadays:

big cities with car traffic. In older times, even large cities might not have 600,000 horses & donkeys passing by

socially, women our days are interested in going to shul and meeting others. Gemora discusses the problem of women wearing jewelry on shabbos as they tend to meet their friends and take it off to show to others. And 100+ years ago, women were left behind at home while men went to shul & tish. So, eruvin are great improvement in this.

internet enable people to get into heated discussions about different rabbis holding by different positions, instead of simply listening to their local rav.

multiple groups with different minhagim routinely live nearby. I know of a Sephardi Rav who tells his people that they can use the eruv together with Ashkenazim, but apparently, he himself used it only for a medical emergency.