e.g. how do you sell 100 million smartphones when the population is only 50 million, and can hardly afford to buy 1 (and certainly not more than 1)? this leads to layoffs
how do phone shops like verizon or t-mobile stay open if people aren't buying? same for phone repair places? more layoffs
more laid off people means less people going out to dinner, ordering pizza, taking trips, buying new cars. those businesses close, and layoff people.
less workers means less tax revinue, either income tax, payroll tax, or sales tax (cuz people ain't buying shit). government offices cut bodies (layoffs) and reduce services. there are now less cops and more potholes.
how do billionaires, whose wealth depends on publicly traded companies and their stocks, keep making money when no one can buy anything? spacex and tesla can make up numbers and stay afloat, somehow, but most stocks will tank.
> how do you sell 100 million smartphones when the population is only 50 million
You don't. You only sell 50 million.
> this leads to layoffs
Why? 50 million people instead of 100 million also means half the employees in the factory, making just 50 million phones instead of 100.
> government offices cut bodies (layoffs) and reduce services
Yeah, but no layoffs (same reason as the phone factory). Fewer people need fewer services. Potholes are indeed a problem. Some roads leading to abandoned places will need to be abandoned as well.
> most stocks will tank
By your argument, those people that can't buy a second phone, also can't buy any stocks anyway. I see no problem here.
So, the economy of scale is still there whether the finances are there or not. If I make 10 pizzas for me and all my friends, Bob fixes all our bikes, Carol goes to fetch water from the well, Dave tends the sheep, etc... All 10 of us are doing our own little economy without money and benefitting from it. What I'm trying to say is there can still be people selling pizza in a collapsed financial system, if we can somehow trust each other to deliver (which is what money does). Maybe we'll end up making our own currency.
All this relies on a basic subsistence right though, us all living in harmony on some commune. If the housing rental system remains in place and demands dollars even though no dollars are available to be gotten, then our landlord is probably going to choose to escalate to violence and won't take pizzas as payment. If the government is going to mandate rent payment in dollars without actually making any dollars available, we have a problem.