I would and one more point to this already great answer: it is not about 21m or the actual tail emission. This is about protecting “changing the rules” attack vector. Once you change this you can start to question block-size, block-times, anything. If Bitcoin is still useful in those few halvings, security budget wont be a problem because fees will generate enough revenue. If not, bitcoin failed, but not because of security budget but because people dont use it.