The offer (so as to say) is delimited to 1K people per year. I’m not really convinced that they’ll really need to apply such a limit in practice, specially for a passport that’s not really very high up in the passport rankings.
See:
https://adoptingelsalvador.gob.sv/welcome
Thank you for the info Ddmr: we tend to run for conclusions in topics we don't fully understand, but everything is a bit clearer with relevant insight.
So it seems that the Salvadoran government is looking for new funding channels, and that it's directly selling the nationality (limited offer: up to 1000 people per year ). If I was in a position where I could spend such amount of money without hesitating, I would prefer to donate it directly to causes I really like rather than any government, even if the latter has the mentioned incentives attached.
Trying to find out an exception, if I was a Cuban for example and got rich thanks to cryptos, I would think about it in order to get the second nationality and escape the country. But I think that this kind of cases are very unusual.