Irrevocable trusts can have income beneficiaries and principle beneficiaries. and the income distributions can begin immediately. Those distributions can actually reduce the principle, regardless of any "earnings" the trust may or may not realize.
In other words, the trust could have an initial balance of $24,000 USD with monthly income distributions of $2000 (which will probably meet the monthly requirement for the visa rentista the next time the amount in pesos is increased).
The reason to have a principal beneficiary in such a trust is if the income beneficiary dies while the trust is active, the principle beneficiary will receive whatever is left at the time of their death.
PS: I mention a figure of $24,000 USD because in the past the requirements for the visa rentista were shown on the migraciones website and, at least at one point, it included that the applicant show that the required monthly income would be available or two years, even though the visas are granted for one year at a time.
PS2: When the current monthly income requirement was raised too $30,000 pesos the exchange rate was 15 to one. That made the target income in dollar $2,000 per month.
That's why I expect a new figure of at least $120.000 ARS per month to be announced in the near future.