That's why there are so many orphaned products. Avoid making irrevocable decisions while tired or hungry. Circumstances can force your hand. It's good to take tough, hard decisions, even if they're painful. It's even better to plan ahead and avoid the necessity for tough, hard, painful decisions.
Nobody can design a perfect technical architecture three or five years in advance.
But if you run into a brick wall in 18 months - that IS your fault. Many a vendor will lead you into that brick wall. Their executives are measured on annual revenue and profit figures, excepting only those who're measured quarter by quarter. The future will just have to take care of itself. By the way, you might wonder who's responsible for the short-term outlook.