Lots of stuff involved. For one, globalization and mechanization are driving forces. The Wikipedia page for pretty much the official term enshittification has a link to another page describing another term "rent-seeking behavior" that means:

Rent-seeking is the act of growing one's existing wealth by manipulating the social or political environment without creating new wealth.[1] Rent-seeking activities have negative effects on the rest of society.

i.e. when something just takes takes takes and never gives, that describes the broken state.

Also in the late 70s, corporations were given enormous power and now they have more power than any individual human beings - even their CEOs exist as slaves to their whims, except to the extent that they also are shareholders in their stocks. Humans have to do things like breathe, eat, die, and pay their debts, but corporations have special legal exemptions and don't have to do any of this. And this even without the extra special stuff done on top of the normal when they are deemed too big to fail - e.g. banks can smuggle money from genocidal terrorists and get away with it, but don't try that at home unless you too are a corporation of at least a certain size, and can afford to bribe/threaten the life of your own personal judge!

And underlying it all is the dirty word politics, an ancient Greek word meaning "how (the process by which) we all agree", or another definition is "who gets what, when, how". Every time something happens, whether it be genocide or school shootings or even just allowing corporations to claim one thing on the internet while delivering the exact opposite of that (without consequences), it is this "politics" that decides the outcome - like WILL we support Ukraine (financially and/or otherwise) to defend itself from Russian aggression or WON'T we? And on that note, there is a fascinating series of videos on YouTube called "The Alt-Right Playbook", which explains why conservatives like what has happened the last 10 years - e.g. not paying taxes is "smart" and Musk taking over Twitter is "his own business/matter", and corporations having all the stuff while we merely working stiffs have none of it is very much not a byproduct but the literal point of the systems, which is very much working as designed. You may call it words like "inflation" and "price gouging", but companies charge what the market can bear, so according to that philosophy, whatever you call it is a good thing, very much not something that government should be doing anything to stop, and in fact perhaps corporations should be given even more power on top of that.

Like everything else - e.g. physics, biology, chemistry, economics, etc. - you are not going to understand everything in less than let's say a year, or possibly a decade, but you will get there if you really want to know. The short answer imho is that giant corporations now have more rights than mere human beings and thus normal folks are fast becoming obsolete. We will either be killed off (a large number anyway) and the rest absorbed into becoming slaves for them, the same as has happened many times throughout history. And we will be shocked, shocked I tell you, shocked, as if this entirely predictable outcome had never happened before and never would again. Basically they are putting in huge efforts to do these things, and very few people are bothering to lift a finger to try and stop it so... how is it not inevitable? About the only thing I see working against corporate enshittification is FOSS and piracy, each providing for free what corporations want you to pay for.

Corporate capitalism.

Profit before people in literally every facet of modern western society.

Years of believing the adage that "we should just be happy to HAVE a job", which ultimately gave carte blanche for companies to treat their employees like line items on a spreadsheet; something to be minimized as much as possible in order to squeak more pennies into a stock price.

Literally every bad thing today is the wholly expected endgame of 80s trickle-down economics.

It was those damned churches staying open during COVID

Covid, war, alt-right fascists, AI, TikTok, capitalism maxed out, climate change, where should I stop?

it's just how capitalism works. Read Capitalist Realism by Mark Fisher if you want to get a better idea of how things got here

Capitalism seems to run in a cyclic manner. If you remember in the 80s we had movies like Wall Street and Other People's Money, because I think things were at a similar point then to where they are now. But, through the 90s (and I joined the workforce in the mid 90s) I recall a more customer-centric view, and even some level of consideration for employees. This has gradually deteriorated starting in the new millennium.

The last 10 years I think has seen this accelerate such that the only consideration for a company is to the shareholders (public or private), customers are in the equation somewhere but way, way after providing value to shareholders via cost-cutting in any way possible. Employees are absolutely just a cost of doing business and if they could eliminate them too, they surely would.

The only hope I have is that I've seen this reverse before, so it CAN happen again. But what makes me place some doubt about this is headlines like the four richest people doubling their net-worth in an incredibly short period. The economy is a zero-sum game, if they doubled their worth other people lost everything, MANY people needed to lose everything to achieve that. Those people need to lose, and lose a lot to bring us back, and I can't imagine they will let that happen.

Maybe things will improve, maybe there will be a revolution/uprising when it just gets too bad. Who knows?

Globalization. Exploiting developing countries, export jobs and environmental damage, hiding profits. Not so long ago corporations had to be careful not to shit where they eat. Now they can shit in Asia and eat comfortably in USA/Europe. Everyone lost on that.

Healthy food costs more than unhealthy food....

Edit: mb, not really an answer to your question, but it sucks nonetheless..