What would such a plan even look like? Back in 2018, how could anyone come up with an accurate timeline at all? Let’s see, first wait for NVIDIA to invent the H200, then…
Maybe I just have a more relaxed attitude being in software, where almost no one can predict timelines within a factor of 3 of the actual number, even for relatively straightforward projects that don’t require fundamental advances. We’re really, really bad at it, and it actually gets worse the more detail you use. In fact, making the prediction at all itself makes the prediction worse, because people start behaving differently when the prediction is made.
I’ve never seen a Gantt chart that ever had any bearing on reality; I’d trust one less than the gut instinct of a senior engineer, although I wouldn’t trust either to less than a small integer factor. If I found someone that reliably made schedule predictions for software products to within 2x of reality I’d think them an oracle.