We keep encountering situations like this where a new chemical compound was introduced, becomes ubiquitous in our diets or environments and only later do we find out "Oops, it has serious health or environmental consequences."
It is worth the cost of slower introduction of new materials to take the time to ensure that those materials are safe. We're still paying the cost of introducing lead into our environment in a myriad of subtle ways. We still don't fully understand what the cost of the introduction of microplastics or PFAS is going to be. And regardless of the whether this particular study holds up under replication it is looking increasingly likely that aspartame is not something we should be consuming.
And what's most frustrating is that the people who profited most from these compounds never pay for the damage they cause to generations.
How much slower would we have reasonably gone to avoid lead?
Pliny speaks of the "noxious and deadly vapour" (sulfur dioxide) of the lead furnace (XXXIV.l.167; there was, in fact, a four-fold increase in atmospheric Pb pollution during the Greco-Roman period); red lead (minium) (XXXIII.xli.124) and white lead (ceruse) (XXXIV.liv.176) as poisonous, even though both were used as a medicine and cosmetic; and the power of sapa (and onion) to induce an abortion (XXIII.xxx.62). Dioscorides cautions against taking white lead internally, as it is deadly (V.103). Soranus recommends that the mouth of the uterus be smeared with white lead to prevent conception (Gynecology, I.19.61). Galen (On Antidotes, XIV.144) and Celsus (V.27.12b) both provide an antidote for poisoning by white lead, and Vitruvius remarks on the pernicious effects of water found near lead mines and its effect on the body (VIII.3.5, 6.11).
The earliest description of acute lead poisoning (mid-second century BC) is given in the Alexipharmaca of Nicander, who speaks of "gleaming, deadly white lead whose fresh colour is like milk which foams all over" (II.74ff). The poet describes a frothing mouth, asperity of the tongue, and dry throat, together with dry retching, chills, delusions, and overwhelming fatigue. But if lead poisoning had been endemic, it presumably would have been remarked upon at the time. And yet there is no mention of the fact until early in the seventh century AD, when Paul of Aegina, a Byzantine physician, described chronic lead poisoning (although he does not associate its symptoms with the disease). "I am of the opinion that the colic affection which now prevails is occasioned by such humours; the disease having taken its rise in the country of Italy, but raging also in many other regions of the Roman empire, like a pestilential contagion, which in many cases terminates in epilepsy, but in others in paralysis of the extremities, while the sensibility of them is preserved, and sometimes both these afflictions attacking together" (Medical Compendium in Seven Books, III.64).