Agree and disagree. It doesn't help the long term projects that can't really lose long term funding because of their nature. I'll use my sacred cow NASA as an example...
Their 2025 budget is $25.4 billion. A proverbial drop in the bucket budget wise, but includes a great deal of long term items that will run multi year or sometimes even decades long. Take the New Horizon mission for example. It launched in 2006 with the express mission of exploring Pluto. It didn't arrive until 2015. So, during that time, they still had to monitor the craft, make sure it was on target, do course corrections, do long term studies of the Pluto environment, etc. They had to allocate money every year to do the routine "maintenance" on the craft until it arrived.
So, long term contracts work in this situation. Was there likely "waste" built into that program? Probably. But the answer to that isn't just "cut 20% next year and hope for the best." It's better to reward savings over the fiscal year (maybe in the form of bonuses or the like) and use the remainder to say, pay down the debt or move to a program that justifiably ran over budget than to just cut outright.
"Here's your budget... if you save 10% or more you get back 20% of that for you and your team in an annual bonus."
It makes coming in under budget and not rushing to waste the money at the end of the fiscal year (here's looking at you DoD) a reward rather than the system we currently have. Do you spend a little more? Yes, but you also save a LOT more when the independent players have a stake in the game.
But that's not a game you can do after one year of studies. Over a three year period is a pretty good start before trimming the "fat" off a budget. "Hey, you spent an average of $170K less than budgeted the last three fiscal years. We're going to cut your budget by $150K next year since you're doing fine." That also makes finding new savings even more important to managers and comptrollers.