"These four types of integrity, do not establish memory safety, but merely attempt to contain the effects of its absence; therefore, attackers will still be able to change software behavior by corrupting memory."
and the paper then goes on to say, about Apple's implementation of the cited techniques:
"This intuition is borne out by experience: in part as a result of Apple’s deployment of these defenses since 2019, the incidence of RCE attacks on Apple client software has decreased significantly—despite strong attack pressure—and the market value of such attacks risen sharply."
"Decreased significantly" is not "eliminated"; indeed, you could paraphrase this as "the combination of these techniques has already been shown to be insufficient for security guarantees".
Which is not to say that these mitigations are a bad idea; but I think their benefits are significantly over-sold in the paper.