Politicians expect their population to consume stuff, to raise kids... if at-will employment were legal I'd have to save and save and save money for anything because I could not be certain to still have a job tomorrow.
Get rid of this shit, impose minimum 2 weeks (better 4) of prior notice, except of course for stuff like theft, assault etc, and watch as your in-land economy rises.
You're not certain to have a job next year (your company, for example, could go out of work; you could be grievously injured; war could sweep through your country). You ought to be saving, saving, saving anyway; building your own savings is the only way to have true security.
For injuries you can be insured, if your company goes out of business there is supposed to be a social contract that takes care of that and if there is a war then everybody has problems, not just you.
Savings are not a true security either, after all, if war breaks out who is to say your savings will be worth anything.
(For people living paycheck to paycheck, four weeks of savings might not be easy to accumulate. But those people can't suddenly start spending more money if they get better job security. So there might be a compassionate argument, but the economic one doesn't seem to hold.)
I worked at one job where a guy was made redundant - for economic reasons, not incompetence - just two months after he started. He'd moved to the area and literally got a mortgage that week, spending his savings on the deposit. Without the notice period he'd have potentially faced economic ruin.
Ignoring the morals of it for the moment, even speaking economically it's better for the country as a whole. How many mortgages are defaulted on in redundancy situations? The employee is bankrupted and defaults, the bank repossesses and sells the house at a loss (they generally go in quick auctions). The company itself may benefit but the overall economic harm to the country is greater imo.
And that's before you get to the compassionate side of things with people who can't afford 4 weeks savings, ie. every minimum wage job in the country.
That is the major problem: those who are poor and don't know their rights are hit the hardest - and this is why at-will should be abolished.
I would think that giving people more rights is more helpful when they do know their rights.
Now, in the US there is a concept of "at will employment", but it doesn't in reality mean what you're alluding to either. IANAL but it roughly means "employees don't get to jerk employers around with random frivolous lawsuits relating to termination". In essence it means that, legally, employers do not need a reason to fire someone. It does not however in practice mean that employers randomly fire people all of a sudden with no payment beyond today, as you imply.
Perhaps for low-end jobs something like what you are worried about happens in the US, but I suspect it happens in the UK too. Certainly in my experience working in the UK then US, and now being an employer in the US, employment conditions as a practical matter are very similar. The major difference I could point to is that in the UK redundancy payments are tax-free. They aren't in the US. I suppose the other difference is that in the UK employees in technical fields tend to have quite long notice periods vs the US. Here, in theory it is possible to depart one job and be working at a new one a few days later.
I'm referencing the UK here because a) the article is about someone in the UK and b) I know about that jurisdiction and the US (only).