Do you have/use a stirplate or no? If not, then that's the reason right there. I've used 10+ month old yeast, that took ~24 hours to get going, on a stirplate. Stepped up a couple times (three starter steps total) and I'm at my target cell count. Second and additional steps always take off FAST too. Like going within an hour or two, and done in maybe 12 hours (tops).