Hi Madhuri!
Beautiful thread and thanks for tagging me 
I think there are a lot of reasons behind the downfall but in my opinion, the most crucial being the blooming of OTT during the pandamic.
We can't deny it has caused a huge shift. I mean, here we are talking about shows in general but I have experienced the shift in human behavior and work culture after those dreaded 2-3 years as people were confined inside their homes and adjusted to that reality. But that's a different discussion altogether.
Coming to ITV in particular, when people started discovering OTT, the major shift occurred IMO. They could pause and come back later, they could shift to anything they liked and most importantly they got to watch stories which are limited, less illogical and immediately chose it over the over the top content.
The next major issue I believe is the refusal of the makers to change their ways. Change isn't necessarily bad. I know at the end of the day it's business but even for a business to thrive, you need to be aware of your customers and their needs.
I know a lot of people blame Ekta Kapoor for ITV's current state but I do feel at least she introduced some changes. Back in 2000s she introduced Tulsi, Parvati who were homemakers and fiercely protected their families. During 2012-2014 era again she tried to show a bit different reality - FLs who had and valued their careers as much as they loved their families whether it was Ishita (YHM) or Pragya (Kumkum Bhagya). This was the same producer who dared to tell a story from a ML's POV (Meri Aashiqui Tum Se Hi) and showed the FL as more flawed. But now in 2025, everything has taken a backseat. No one is even remotely trying to touch issues that are prevalent in today's society. Then how will the audience be able to connect?
The younger generation obviously will reject this and the a significant portion of older generation too now prefers OTT.
What's worse, the channels now pressurize the PHs more and story keeps jumping from one end to another without any consistency which makes it even harder to root for a character/couple/story.
I would still say the barring from a few actors, I think the new actors have performed well when they were given substance. But ultimately it's the storytelling that has completely gone to dogs and now people don't feel compelled to sit through the torture anymore.
82