so while walls is a breakup song, i could never totally figure out what louis meant by "i watched them all come falling down for you". then it hit me today that he is singing about how he watched as all the walls fell down for the person who walked away from him and that person only, but not for him. because next, he sings "these high walls, they came up short; now i stand taller than them all", which basically means to me that the walls did NOT fall down for him, but even so, now he has overcome them. that in the end, the walls did not stop him, they didn't break his soul.
also not to mention these lines in the first verse, "the day you walked away and took the higher ground, was the day that i became the man that i am now", clearly stating how the ex got away to the "higher ground" (usually a metaphor for a safer place, where the walls would not be high since the ex themself was on higher ground and thus the obstacles were obsolete to them) and left louis alone ("waking up alone"). and this turn of events changed who louis was before into the man he had to become now to move forward ("he were a lot sweeter").
in the second verse, he sings how "nothing makes you hurt like hurtin' who you love; and no amount of words will ever be enough", (which is a sweet, sweet lead up to this part of the bridge too=> "oh, oh"). here, he seems to acknowledge some hurtful conflicts that might've happened during the relationship but concludes that now, no matter what the other person would say, it can never be enough, as -"i looked you in the eyes, saw that i was lost; for every question "why", you were my 'because'". louis saw that to his ex-partner, he was lost, and did not matter anymore; but for louis, his (ex)partner was still the answer to all of his questions, still his choice. this revelation probably also helped himto "wake up" further from the relationship and to start to let it go.
louis watched these walls fall away easily for the ex while for him, they were still obstacles. this is why the bridge seems even more "bittersweet" in retrospect. like how i mentioned here, he directly called out that person through his "thank you for what you did to me", and then finishes with "i hope that one day i'll see you and you'll say to me, 'oh, oh'". he omitted what he wants to hear presumably because it has already been done, the walls have been built, it cannot be reversed. so whatever he wants that person to say to him wouldn't even matter in the long run and thus isn't even worth mentioning.
and the last line's callback to the first line is so genius since in the first verse, it might be the first time louis is waking up alone, disoriented and taking in his surroundings, not fully knowing what has happened. he sees that all that is left of his relationship is simply a cupboard full of clothes (clothes usually being everyday mundane things, but here they become heavy, associated with that ex and all the events that transpired, the cupboard thus full of bittersweet memories and unpleasant baggage). while the last "nothing wakes you up..." is when he knows everything. he lived through it all and came out on the other side. he might be waking up alone, but he stood his ground and persevered. which is why its his final word.
walls, to me, has always stood out as such a complex song. its so melodically soothing and beautiful but the lyrics have me in shambles. it is so so layered and yet so cohesive and meaningful. which is also why it seems so fucking apt as the album title too. it holds oceans worth of meanings in less than 4 minutes.
this got wayy too long than expected, but if you read it all, then thank you so much!!