... And they consistently complain these alternate economic models can't solve these problems and that the free market monetary system is the superior model.
Well. Prove it. ...
It is far from perfect, but does not collapse* within an average of three or less years in the 1000 or so times it has been tried.
It does not suffer from the low productivity of almost all workers are doing the least required.
As a productivity incentive, it gives electronic coupons in crude proportion to the worker's productivity, that can be exchange for what each consumer desires, not standard supply packages that provide many item few desired but some need like diapers, that are in such excess they have no barter value - so about 98% are just trash canned.
I. e. your alternative is very wasteful as it tries to dictate what people should want but don't so they discard many undesired items.
It rewards people very well for years of hard study, even a decade or more, so they do that effort. Your alternative would be lucky to have even 5% of the skilled medical specialists that are needed.
It encourages innovation and risk taking as people open new businesses in hope of growing rich as they grow, even though they know most such new businesses fail.
That is a businesses that transform material resources into product with little public demand soon disappear (unless occasionally "bailed out" by the govern) but not when the government (or "supply package content setting authority," if you prefer that terminology) can keep on wasting resources forever by putting items of little demand it deems "good for you." in supply packages.
You can leave your farm to your heirs, but in your system there is little or no incentive to take good care of land you farm as you get old - your son can not get it - some stranger likely will. (As you grow old and "warn out" so does your land.) I.e. your system is efficient in transforming good farm land into poor soil land few even want.
BTW, I can not speak for others, but I have never complained that your system would fail to solve the problems that do exist in the current system - only that your system adds many more new and much more serious problems, such as listed above, to those that do exist in the current system, while solving none of the current problems, especially if history is any guide.
* Some of the 1000+ avoided collapse by switching to family ownership and management of farm land and begain to use money as flexible means of exchange and store of value for future needs /desired, like retirement and medical care by well paid doctors. NOT ONE, which remained true to the "no-money, collective production especially farms and, all share equally" creed /beliefs survived! A few with common, strong religious beliefs many have survived for a decade.
As George Santayana said: "Those who can not remember the past are condemned to repeat it." You want to make it 1001+ failures.