No that logic is a bit off. You shouldn't be benchmarking against your past self. You should be benchmarking against what you could get elsewhere and, more importantly, what you're actively getting now.

If you found yourself getting a similar TC excluding the signing bonus at another company, and have reason to believe that's actually a fair price for your labor, the cash signing bonus will still more than offset your switching costs. It's also, simply put, an absurdly high bonus. Nothing stopping you from collecting another one of those in a couple years at another company.