I don’t think the parent was implying that it took them 4 years to design a keyboard but that once Apple made a new design they expected it to last a minimum of

I don’t think the parent was implying that it took them 4 years to design a keyboard but that once Apple made a new design they expected it to last a minimum of 3 to 4 years. So they could’ve fixed it earlier but they insisted on getting their 3-4 years out of the original design.