Right... then later when "the Boss" talks to his boss...
Big Boss: "Why haven't you delivered the product yet? I was expecting it midweek?"
Boss: "Well, uh, the team you see... well, they don't think they can deliver... and... "
Big Boss: "If your team can't get this done on the timeline this company needs, get a new team. If you can't do that, then I guess I need a new manager."
Boss: "Yes sir, I see your point."
[Later, with employee]
Boss: "I thought I could give you till the end of the quarter, but we need it tomorrow. Oh yeah, and there's extra requirements now."
Employee: "But you...."
Boss: "I've been overruled and just couldn't push back. You know how it is. Have a good... productive night."
Yup, this is exactly what happens. Basically the same as the "make whoever is in front of you happy until the big boss puts his foot down" anti-management pattern. It can work for periods if the big boss knows what hes doing and respects the employees, but otherwise, destined for disaster.
You don't want a complete pushover, though, otherwise nothing ever gets done while your team is busy playing video games all week. What you want is a reasonable boss!
Additionally, pushover bosses won't stand up for you when Scope creep starts to happen. Before long you will have 20 new change requirements to do in the last few days because someone decided they like the old-old way. (ie the code you just tore apart to appease their previous request)
What's worse is having a boss that's a pushover in one direction. From above, it's always whatever upper management wants, and to his team, it's do it now or you're fired.
You want someone who makes you justify your estimates, so you don't run wild, but is also willing to be like "yeah that really is gonna take 3 weeks longer, go do good work, I'll get you the cover".
I dunno. There's advantages to having a boss that's a huge pushover...
Boss: "We need this done by the end of the week!"
Employee: "That's just not possible. These sorts of things take research and most importantly, time."
Boss: "Oh. I see. Two weeks OK?"
Employee: "At least a month. Maybe two."
Boss: "But that's too long!"
Employee: "Nine women can't make a baby in a month!"
Boss: "Oh alright. You've got until the end of the quarter."