The plan may be critical of our past actions. It is true that part of planning is to review the past and what brought the organization to its current situation, whatever that may be. So certain individuals, even entire management teams, may prefer to avoid scrutiny by avoiding forward planning entirely. For fairly obvious reasons, this is a dangerous attitude and hopefully will not carry the day. The plan may suggest additional expenditures that we can't afford.
Every company has limited resources.
Or at least no company has unlimited resources. The conflict between company goals ambitious or even modest and limited resources is ever-present. The challenge in planning is to make the best possible use of those resources, whatever they may be, to deliver the best possible future for the company. Whatever the resources are, that becomes part of the equation. The plan must be practical and deal with the realities of the moment.