My PhD was some of my best years of my life, and I was truly lucky. It was a once-in-a-lifetime thing, and even now I wish I could return to being a PhD student for the rest of my life. I had a great set of friends, all the research freedom I wanted, supportive department, and I did research internships at least once a year so my average salary was pretty decent (about half a software developer salary at that time). If your goal is to make as much money as fast as possible, then you will be disappointed with a PhD.
I was in a department that was in between social science and computer science, and out of the 8 of us that started together, all 8 graduated. 7 of the 8 landed R1 tenure-track faculty positions, most of us directly after the PhD (the remaining 1 was running a successful business).
Your advisor can drop dead, get sent to the hoosegow, lose grant funding, lose tenure, or change jobs without taking you along. Your research topic could turn out to be controversial among feuding members of your committee. You could be subjected to harassment, discrimination, etc. You might have to escalate matters with your advisor in order to get your final thesis approved, meaning you get your PhD but without a vital source of recommendation.
Some of those things can happen to you in a regular day job as well, but at least when you lose a regular job, you haven't lost everything.
It's also useful to note that the money and working condition issues are country and field dependent. For instance, in many European countries PhD students in many STEM and also humanities fields are most often employed full-time with standard work contract(s), with OK salary (but less than in industry), and full benefits with excessive unpaid overtime in principle forbidden, small or no tuition, etc.
The situation with academic career prospects after PhD as I understand however is that situation is similar to US everywhere, and going eventually gets tough after that point, and most people are culled before finding a "permanent" position.
Through scholarships I was paid enough to be comfortable while spending my time on interesting things. The scholarship game is a bit winner-take-all though, and I know the minimum funding level in my department was less than 1/2 of what some of us were making, and that was in a STEM department - my understanding is humanities are a very different thing. You have to decide what is ok for you.
Afterwards I did a post-doc and then a research position. Through a national fellowship (post-doc) and funding guarantees (faculty) I knew I would be able to make something like the low end of what my industry salary would be - and easily chose the academic freedom at least for a few years.
When I was on the academic market, I didn't find a tenure track position I felt was the right fit. Rather than play the waiting game some of my colleagues were doing, and I realized that "any R1 that will take you" wasn't going to make me happy. So I chose to turn down the offers and go to industry. That's also had it's ups and downs.
I guess my point is there where many steps along that path I took a good look at my options and chose to stay. Sure, I could have made a bit more money in some industries, but there are other considerations. I've never worked with a more talented or motivated group of people than I did during graduate and post-doc work. I've never had the time since to just dig into an interesting problem or really swing for the fences. I'm sure it cost me a bit in terms of lifetime earnings, but it's a trade-off I'd make again in a heartbeat. I'm sure I would have been happy teaching somewhere if the parameters had been slightly different, but I'm ok with that too.
What I really don't understand is people who are somehow shocked to find themselves in the position, many years in, of making less than they think their time is worth and without the career prospects they had hoped for, and bitterly complain about it as if someone else made the decisions that put them there.
Graduate programs absolutely aren't for everyone. They are, however, a unique opportunity - if the good parts really appeal to you and the financials etc. make sense for you, by all means do it. Just don't expect it to be something it isn't.