I'd guess the lack of celebration has less to do with the show's enduring popularity than its current ownership. CBS and the show are owned by Paramount, undergoing a controversial merger. I doubt there's anyone in the vulture capitalist leadership who cares much about the legacy of a 75 year old show, no matter how beloved.
But, also, what's left to say? I'm as hardcore of a fan as one will find, and I've skipped recent-ish documentaries and awards about the show. Other than Keith Thibodeaux, there's no one left to share any recollections. The show has been celebrated, written about, analyzed and discussed for 75 years. Even the ILL reddit group -- by far the most active fandom of a classic sitcom -- is mostly reduced to exhausting nitpicking.
There's this one lady on YouTube, Marina Coates, whose channel is dedicated to making 3D copies of houses/apartments from famous TV shows/movies. Her work is incredible, and among them, have been three of the residents that the Ricardos/Mertzes had stayed in during the show's run.
Ms. Coates has also done a video that showed a dream concept of hers about a theme park that is comprised of all the famous sitcom homes from the 50s, 60s and 70s:
https://www.youtube.com/watch?v=-y3I9mGVJtA&t=331s
I'm aware that Universal Studios does occasionally have a "Lucy" character walking around, but the above theme park would allow for a fresh new focus on ILL (and all of the other sitcoms) by making the sitcom world far more interactive and immersive. Heck, I even came up with SEVERAL ideas for this park's ILL section:
I would have the Ricardo's Connecticut house be attached to a four-story building (with the staircase in the house's living room leading up into the building), and on stories 2 thru 4, would be their first apartment, their second apartment, and their Hollywood hotel. Outside the 3rd story apartment window would be two mannequins positioned on the ledge: one would be Lucy in her Superman getup, covered in pigeons as she presses herself desperately up against the building's wall, while the second mannequin would be Superman standing in the same pose the original actor made when he said, "And they call ME 'Superman'!"
I would even have there be an elevator for guests who don't want to walk up all of those stairs, and inside said elevator would be a bellhop... who is really "Lucy" in disguise, trying to catch sight of any Hollywood actors (and if anyone ever mentions Cornell Wilde to her, she is meant to look nervous and say she's actually avoiding HIM

).
As for the first story of this building, I would have that be where the dining/shopping occur: there's a candy shop filled with references to the "Job Switching" episode (including staff wearing the same uniforms Lucy & Ethel wore; plus I'd have each candy box come with complimentary cards that read "Happy Birthday/Anniversary/Valentine's Day/etc" as a reference to the episode "Ethel's Birthday"); there would also be a diner/pizzeria, both of which would be modeled after "The Diner" and "Visitor from Italy"; and finally, there would be a boutique where customers can buy outfits that look like some of the costumes the original actors wore (vintage fashion is very in these days; I can see a lot of women eagerly buying the dresses that Lucille Ball and Vivian Vance wore).
Finally, I would also finish off the ILL section with another building that's basically a recreation of The Tropicana. Customers can go there for a fancy lunch or a dinner (they'd even be encouraged to wear the outfits they bought from the boutique) and be entertained by a Cuban band and an actor/singer playing the part of Ricky Ricardo... and of course, there'd be an actress playing Lucy trying to get into the act, with the Mertzes making an occasional appearance.
It'd be a great opportunity to come up with new skits and shenanigans for these characters to go through. Heck, the Tropicana performances could even contain crossovers with other sitcoms! Imagine Lucy meeting Jeannie or Samantha, or Ricky doing a musical number with the Brady kids! Silly, yes, but come on, it'd be tons of fun!