Why did the IDF attack on Hamas's 'Metro' not go as planned?

The demolition of the tunnel in the northern Gaza Strip, known as the "metro" did not work to the expected extent.

An IDF artillery unit fires towards Gaza Strip near the Israel-Gaza border in Southern Israel, May 13, 2021. (photo credit: GILI YAARI/FLASH90)
An IDF artillery unit fires towards Gaza Strip near the Israel-Gaza border in Southern Israel, May 13, 2021.
(photo credit: GILI YAARI/FLASH90)
The IDF attack on the "Gaza Metro" did not achieve its goal.
Thursday night's "Metro" operation had been in planning for several years, but due to the fact that a ground operation at this stage did not sound credible, many Hamas forces did not fall for the bait.
It appears to be that the operation did not achieve its intended purpose, as "the conditions for its implementation did not materialize." 
The strategic operation had been planned for at least three years, and was part of a plan backed by impressive intelligence.
The demolition of the tunnel in the northern Gaza Strip, known as the "Metro" by the IDF, is just one part of the plan, but not the main part. It is estimated that between 300 - 400 people were killed.
According to the plan, Hamas forces were supposed to enter the tunnels in response to the IDF's announcement of a ground maneuver, but it appears that this tactic did not work, or at least worked only partially, and certainly not to the expected extent.
Within the military there were people who argued that the execution of the operation should have waited, because the conditions were not right, and that it would have been preferable to wait until a ground operation would be seen as credible.