Aiming an artillery rocket requires setting it to the correct elevation and azimuth. The elevation is relatively easy, since a fixed-elevation ramp can be pre-fabricated. The azimuth setting is harder, but by using a high-precision compass and surveying and marking many launch sites, rockets can be launched with minimal preparation, from a large number of locations, at many targets. If a few rockets are stored in camouflaged locations near each launch site, there will be no vulnerable transport link for the defenders to interdict. The rockets would be launched by a timing device to allow the launch team to escape a retaliatory strike.
Hezbollah has had many years to come up with a cheap and robust scheme for launching rockets against Israel. How could Israel counter this scheme?
Assuming that Hezbollah is launching from pre-surveyed sites, Israel will gradually catalog all the sites, either by radar plotting of the rocket trajectories or by sensor detection of the thermal signature of the launch. The reason we are seeing so much TV coverage of Israeli howitzers firing into Lebanon is that these are the primary killing tools used to neutralize rocket launch sites. It is doubtful that these fire missions are doing much more than busting up some cheap launch racks, and occasionally hitting a rocket cache. The fact that Israel has fired over 20,000 artillery shells into Lebanon without diminishing the rate of incoming rocket fire substantially suggests that there are hundreds of launch sites.
If Hezbollah has developed a method for mobile setup of launch sites, then the defensive problem is much more difficult, since the attackers will never run out of pre-surveyed sites. However, through persistent surveillance, the defense will eventually uncover the location of the rocket storage sites that are feeding the launch teams.
I believe that the reason that Israel has had poor results to date in suppressing the rocket fire is that it misjudged the scale of Hezbollah's artillery rocket program and did not allocate sufficient reconaissance resources to locating rocket sites and teams. Israel probably needs hundreds of surveillance RPVs and monitoring teams watching Lebanon, when they have only dozens.
Israel will adapt its tactics and adjust its resource allocation to end the current rocket threat, but what kind of "victory" will this be? The Hezbollah rocket launch teams are not highly skilled and can be replaced in a few months. The rockets are cheap and easily smuggled into threatening locations. Rocket accuracy will increase steadily as inexpensive guidance systems allow even the crudest artillery rockets to become precision guided weapons.
The evolution of military technology is moving against Israel. It will become steadily cheaper and easier to attack Israel with rockets. It will not become easier to defend against them. Israel needs to put more emphasis on diplomacy and less on military force, because the military option will become progressively less effective in providing security.