Anderson Silva is a complete fraud. Even if he wasn't on steroids his entire career, he still fought mostly weak competition. Weidman is the greatest fighter he ever faced and he got exposed badly... twice.
He was also fighting in a smaller weight class than he should've been. If silva was any kind of GOAT he'd have joined the much stronger Light Heavyweight division at that time. That was a weight class where everyone was his own size. But he dodged it like the plague. The 3 times he fought 205lbers he picked guys who were tailor made for his style.
At no point in Silva's career would he make the top 3 of todays middleweight division.