In answer to the question in the OP:
At the time SSB was started, Browne was already elderly and in failing health. That said, of course the site made a difference and contributed to her downfall!

As tough as it was to work on at times, if even one person was dissuaded, it was all worth it. Even if you simply poured fuel on the fire, you did a very good thing.
The only regret I have is that some site like SSB wasn't created years earlier, before Browne became big.
Full disclosure: I researched Browne for years and so had a huge emotional investment in the site at the time. I did think of it as "my baby" (I hope Robert won't mind). So this is a highly biased opinion.
Grieving people are at best a very small percentage of Sylvia Brownes business they are only the ones most talked about. The vast majority are people who are too lazy and too stupid to do the leg work to solve their own life problems.
They are willing to pay anything for someone else to make decisions for them.
I attended a taping of a Sylvia Browne episode and, though I did not survey audience members and get hard data, I think nearly
everyone there had recently lost a close family member, significant other or friend. Based on what I heard, I'd say 90 to 95 percent asked about a dead relative. What a glum, depressing atmosphere. Everyone was sad and unsatisfied, filing out of the studio when the taping was over.
It was a shock to realize, part of the way through the taping, that the only person there who
hadn't just experienced a death was me. And possibly Williams and Browne.
On another note, this is obviously anecdotal but I believe that a significant percentage of the audience for a Sylvia Browne show has depression, bipolar disorder or some other mental heath issue. The questions that they asked betrayed this. A lot of people would say things like "I feel like I'm stuck in a rut, job-wise and personal life-wise. I've felt this way for years and see no way out." or "Everything seems to be going wrong for me, so much so I wonder if I'm cursed".
With the caveat that I am not a psychologist, I think a lot of these people have undiagnosed depression, unbeknownst to themselves, and need to stop seeing psychics and start seeing mental health counselors. The things they listed (extreme loneliness, oversleeping or undersleeping, constant fatigue, failed personal relationships, lack of workplace success, extreme lack of self-esteem, boredom, hopelessness, lack of joy in life) sounded like classic symptoms.
A lot of them had
diagnosed bipolar disorder, schizophrenia or some other mental disorder and would outright say so and ask Sylvia questions about their illness. I felt awful when one audience member asked Browne when she would be cured of a disorder she had been struggling with for decades and had been taking heavy medication for and Browne said "Next year", which prompted the woman to burst into tears of relief and joy.
So I don't fault this segment of her fans. They are desperate to find a cure for their problems and will turn to everyone and anyone who seems to offer answers. They have not considered the possibility of depression, perhaps through a lack of education about it. The very nature of their illness predisposes them to a belief in the supernatural; plenty of psychologists will tell you that the clinically depressed are prone to "magical thinking". How can you blame a desperate, tormented schizophrenic for a poor grasp of reality and having cloudy judgment? Of course they cannot think straight. That's what being schizophrenic
means!
By the way, that's another example of the harm that psychics cause. People look for a supernatural answer instead of a medical, psychological, environmental or practical one. They take their problems to the wrong person, who will lead them in the wrong direction or none at all. Browne would make predictions like "You feel you are stuck and want to know what will happen next? I see you going into something creative in the future, maybe art" instead of telling them "You need help, preferably in the form of someone who can prescribe anti-depressants in the state you live in."