Ok so what amount of the budget does this represent?
Maybe a percent or two, but with a budget is big enough, that's still a lot of money that could be used for something else.
The point is not that any of these things individually will result in big gains. The point is that there are a lot of different small inefficiencies that add up to a bigger inefficiency.
For example, for some reason, when the IRS sent out their findings for tax exempt status, a group that I work with never got the determination letter. And the IRS had no straightforward mechanism to resend the letter. Fixing it involved hundreds of phone calls before we reached a person who could help, and then waiting for someone to print it and mail it to us. All of this stuff should be in electronic records, and it should have been trivial for us to directly get a new copy electronically from their computer systems without requiring a person at the IRS to intervene.
Every time a person has to do something because a computer lacks code to do it, that is an example of government waste. It probably isn't worth fixing all of them, because sufficiently rare things could take decades to recover the cost of coding them, but that doesn't mean that someone shouldn't triage them, catalog them, prioritize them so that the scope is fully understood, because when you do that, you may find other people coming in later and saying, "If you do that, it will save me time on related task [x]," and that might then turn out to push it into "implement this ASAP" territory. Without documenting the state of things, those discoveries won't ever get made, and nothing will improve.
And the IRS has multiple incompatible login systems that use different credentials, multiple sites that expose different parts of the same access to information about your business/charity, etc. all of which have to be maintained, resulting in massive levels of redundancy, not to mention causing massive confusion for anyone who ever has to access them, wondering why it says they don't have an account even though they had to have one to fill out previous IRS paperwork. Replacing them with different views into the same data (with access right limits, presumably) in the same online system would likely save significant money, both in terms of software maintenance costs and server operation costs.
And how much auditor time could be saved if they trained AI models on previous audits and used that as a starting point for flagging suspicious returns and/or filtering suspicious returns flagged by existing automation? I don't have any idea, but I would not be surprised if that approach eventually produced meaningful long-term savings.
And every time they send out tax forms, what manual processes have to happen to distribute advance copies to companies like TurboTax, and how much time would be saved if we had a centralized, modern electronic version of all of the forms, rather than PDFs, with an open source implementation, complete with code to populate one form from another, etc.? Maybe it would cost more initially, but would save money in some other areas, like making it easier for auditors to recompute the taxes after fixing errors in data entry. I'm not sure, but these are the sorts of efficiency wins that should be looked at.
So in that one division alone, there are glaringly obvious inefficiencies that, if fixed, could result in considerable cost reduction. Similarly, every time you deal with someone at the Social Security Administration or (at the state level) the DMV and they tell you that the computer system is down and they'll try again in a minute, that's an example of government waste. It's a system that isn't working correctly, which as a result, wastes the time of hundreds, thousands, even tens of thousands of government workers on an ongoing basis.
There's no reason to believe any other part of the government is any better. Government IT is known for being disastrously slow at modernization, and it costs taxpayers a lot of money because our government doesn't spend the money to bring those systems up to date in a timely manner.
These are just some examples that are obvious from the outside looking in; there are probably many less obvious examples that would be obvious to someone who works there every day. And that's the point. The people at the top can't see what wastes the time of the people at the bottom, because they don't have visibility into their minute-by-minute activities (and even if they could, they would have a hard time filtering the flood of data into something useful). So you have to drive efficiency from the bottom up, and our government does not do this, so we can never really know whether that inefficiency adds up to half a percent or ten percent.
We can't get a complete picture without going to the people at the bottom of the org chart and asking them what could be done to make them more efficient, what could reduce waste, etc. It's a relatively easy low-hanging-fruit task, so we should do this. :-)
I hope that makes my position clearer.