They certainly do - its how every company operates. You think I can stand up to my finance guy after they 'adjust the plan' and tell him "no you can't tell me there is a hiring freeze, I had this budgeted!". Or when a natural disaster hits, a company says "oh well, we can't get back online until next year because we didn't budget for this!". Or when the CEO sees a market shift and says "we need to act... " - Sorry Chuck, you didn't budget for that, so go back and talk to me next August. LOL
The finance team holds the purse strings and uses budgets to PLAN and MANAGE spending - The budget is not above the business, the budget serves to manage and plan ahead. When circumstances change, they adapt. They shift priorities, they take from Peter to give to Paul, they slow some things, speed others. This is month to month in the real world.
Or even what Disney faced this year - Their budgets they planned a year ago are in the trash now... because they didn't know what they'd have.. just like their FY2021 budgets got trashed when the shutdown hit. The budgets are plans - not blood contracts. They get altered all the time when circumstances or business needs dictate.
Wall Street doesn't have a freaking clue what the budget is. The company forecasts revenue, margins, and profits... not the budgets of how they get there. Finance manages the big targets by massaging and working the smaller targets.
A business that puts the old budget as untouchable would be a company that can not react.
My company runs forecasts 3 times A WEEK tracking activity and the sales funnel. Even non-sales activities are managing budgets monthly to quarterly. NOTHING is assumed a given. Because they all know if the faucet slows, so does the spending... and if things are not going to plan, you better be proactive, not procrastinate to have plans adjusted so there isn't some big pinch people weren't expecting.
Ok great - operating expense. See that corporate travel and security budget doing ABSOLUTELY NOTHING... reallocate those OpEx dollars.