Allah (swt) could have made it clear to the Prophet (sa) and to us exactly which date Laylatul Qadr is. But He didn’t. Instead, he inspired the Prophet (sa) to increase worship on all the last ten days of Ramadan.
In fact, the exact date of Laylatul Qadr was revealed to the Prophet once, but that knowledge was again taken away.
“Allah’s Messenger (ﷺ) went out to inform the people about the (date of the) night of decree (Al-Qadr) but there happened a quarrel between two Muslim men.
“The Prophet (ﷺ) said, ‘I came out to inform you about (the date of) the night of Al-Qadr, but as so and so and so and so quarrelled, its knowledge was taken away (I forgot it) and maybe it was better for you. Now look for it in the 7th, the 9th and the 5th (of the last 10 nights of the month of Ramadan).’” (Bukhari 49)
Note that the Prophet (sa) said “maybe it was better for you” that he forgot.
