I disagree. While the suttas are written to make it look like Siddhartha Gautama had a huge following, if you read between the lines, especially in the Samyuta Nikaya, I believe you will see that, while Siddhartha Gautama was not persecuted, he was not as lionized in the way the suttas want us to believe.
On the other hand, there are a number of references that indicate that Siddhartha Gautama was given lands "parks", and possibly even buildings, where he and his followers were welcome to reside; however, those lands and buildings do not seem to be present in his later life; and it almost looks like it was Siddhartha Gautama who rejected them, as a temptation that might make his followers too soft, or the lands were taken away.
Additionally, in the Samyuta Nikaya there are a number of references that indicate a period of mass suicide among his followers during at least one rains retreat. I believe it was his last rains retreat before his death.
The suttas are not specific about what he said, but they clearly state that he spoke to his followers once, then he told Ananda that he was going into seclusion and not to bother him for anything.
It is a fact that both Mugallona and Sariputta died before Siddhartha Gautama. It is clear in the suttas that Siddhartha Gautama was very pleased with those two students of his; and I believe he felt he could die and leave his mission in their good hands. But, when they both died in his 80th year, I believe, he felt his whole mission had been wasted, and that is why his last discourse discouraged so many of his followers that 500 of them committed suicide.
Later, after that rains retreat, he ate his last meal, which he knew was poisoned. That is suicide. In conclusion, while Siddhartha Gautama was not necessarily marginalized, but he certainly was not lionized, and I believe he felt his work had been completely wasted.