miss the boat

miss the boat AND miss the bus
(fail through slowness; to put something off until too late)

Example: We wanted to buy the carpet we had set our heart on but at the shop we found we had missed the boat — the carpet had already been sold. — Мы хотели купить ковер, на который раньше положили глаз, но в магазине выяснилось, что мы пришли к шапочному разбору — ковер уже купили. Поезд ушел...

Related vocabulary:
[поезд ушел]
That ship has sailed!
[прийти к шапочному разбору]

blow sth
informal completely bungle (an opportunity):
......he’d been given a second chance and he’d blown it