It's amazing how often I've seen projects - even strategic / multi-million buck ones - being planned "on the back of an envelope".
Some dude shits out a guesstimate that's then slapped in a powerpoint and it becomes the target & budget which is handed to the luckless PM and the dev team.
Getting the right people involved, and going into detail on scope, spec and architecture etc. is not "wasted time and money" but instead an investment; these are activities that will have to be done (or should be done) eventually anyway...
Of course, the estimate is often higher than key stakeholders "guessed", hence the popularity (as mentioned in another post) of the cynical "lowball then come back for more time and money later" method.
Then we get posts like this saying "development is impossible to estimate". Bullshit; with a competent PM controlling the scope and a tech team that know their stuff it's not that hard.