How many people do you know who “failed to meet the standard”? Zero. If you do the time and work for your professors you will get the reward. There is no risk.
> PhD Envy" is a real part of office politics
The most vocal critics are not bachelor degree holders, but those who did it and had a bad experience.
It could be because you realize you don't really like research - that involves reading and writing a lot of papers, going to conferences not just tinkering. It could be because you had the wrong professor who failed to lead you and left you by yourself. It could be because you gave up at a low point, where most PhD student go through. It could be because after 4 or 5 years your professor keep saying "you're not ready yet" (I've seen that in humanities).
So it's not really a problem of "not being good enough", but it definitely happens.
1. Your experiment fails to produce a result after a few years of effort (my project, we don't know to this day what went wrong, and I was lucky to find a new project).
2. Loss of funding or institutional support. (A large program at my state's university pulled its support for a process that required regulatory approval, and an entire group of faculty and students all had to leave.)
3. Your advisor quits, changes jobs, gets fired, goes to prison, dies. (Many cases).
4. Your advisor holds your thesis hostage until you publish a certain number of articles (a friend of mine, she sued and won).
5. Mental health issues (high incidence of clinical depression).
6. Personal animosity between members of your committee (another friend).
How these risks instantiate themselves is that you have to start from scratch, often with a completely new research project, and finding one isn't guaranteed by your department. You are almost completely at the mercy of one person -- your advisor. There is virtually no oversight.
Most of these are factors in any employment, and I would argue things like chance of losing funding at your job is worse than academic funding threats.
Also, this is HN, which revolves around an occupation -- computer programming -- that is unique in terms of having high demand while remaining flexible about how and where people learn their skills. Not all fields are that way.
I got a PhD in physics, in 1993, and have worked in industry since then. There are a couple of "negatives" that I still think are wroth pointing out:
1. PhD programs have very high attrition, and you bear most of the risk on your own shoulders. It's worth going in with eyes open, and knowing the risks. Getting out with your PhD may require some compromises along the way. I won't necessarily call them ethical compromises, but perhaps compromises to the (typically) idealistic views that many students start out with.
2. The little nub of specialized knowledge shown in TFA is your research, not your brain. You can do specialized research without becoming a specialized person if you want. This is a personal choice (academic freedom and all that). My dad, who also had a PhD and a good industry career, always told me to avoid hyper-specialization.
Don't forget to learn how to code, just in case. ;-)