Try reading your own article. It does not support your position that "walls don't work", which is an erroneous black or white proposition. "Some were arguably quite successful, others less so." That point is made early in the article, and it's obvious to anyone capable of rational thought that walls have to be supplemented by additional strategy, which used to be the policy for our southern border.
We also need troops and surveillance to stop the flood of illegal invaders that are pouring into our country, not the Democrats' open door policy that makes us the world's homeless shelter. The 3000 breaches in the past two years is a direct result of Biden's order to abandon the wall, not a failure of the wall itself. We could slow this incursion to a trickle if the wall was completed and proper defensive policies that deny sanctuary were in effect. We should also work with Mexico to keep these hoards from getting to the border in the first place.
In summary, the article also states:
"As long as life in the United States offers potential migrants more opportunities and fewer perceived dangers than their home countries, illegal immigration will likely persist.
If a border wall provides the political space for addressing these more systemic problems, then it may still be a worthwhile investment."
In other words, we need to stop all the free food, housing, health care, education, citizenship promises, etc, that encourage anyone and everyone - including criminals and terrorists - to come here. This country has always had effective policies to manage legal immigration and political asylum, and we need to go back to those methods instead of welcoming chaos. The wall along with other barriers should be part of that plan.
www.bbc.com
www.rand.org
