The other way to interpret is until you find the materials for the 4th LB. In that case...
List of mats:
5 orichalcum (GO drops)
20 wind regalia
20 wind fangs
30 tier 4 stars
15 silver books
10 gold books
Not way too demanding. I think. By the time you get enough bricks from the tower you should have gathered enough mats to 4LB like 3 dragon eye weapons. If you actually have 3 3LB dragon eye weapons that is lol. The irony
That seems to counter conventional wisdom as far as I'm aware.
Event SSR weapons are in a sense, renewable. At least, the advent and the union ones. Raid ones are obtainable by orichalcum, but they don't even have 4LB so their worth is debatable. Then, we add the fact that they generally have lower stats than gacha/ dragon eye weapons. Why would one spend bricks on those?
... Unless I'm misinterpreting (I'm particularly bad with pronouns lol), as I believe I did Slashley's.