Right the problem with UBI is the people being productive in some way to fund it will always see the level of benefits as too much and those on the receiving end will see the benefits as too little. So as a higher % of people are on the receiving end, it creates a spiral of unfundable benefits demands.

Look at France, it seems like the biggest protests now are when it is suggested their retirement program is unsustainable and they should phase in a higher retirement age. And these programs across the west are becoming unsustainable because retirement ages were set decades ago at levels 0-10 years below life expectancy, and that gap has now grown to 20 years with a lower employed:retired ratio.