You couldn't buy it from Newegg. You'd probably have to buy it from gsaadvantage.com. A whole website built around fleecing the government. If they didn't have it on there, or you needed it now, or it was impossible to get shipped to you, you'd have to attempt to purchase it on the local economy. But of course, that means you can't buy at national chains (Walmart, Home Depot, Lowes, etc.) you have to purchase from a place that's locally owned, and on an order of preference list based on if the owner is a racial minority or woman. The end result is that when when we need to get some ramps so that we can drive the lawnmower into the storage unit we have to drive an hour each way (in a .gov truck using $4\gal gas) to a "locally owned" hardware store and pay 70% more than the same item costs at Lowes, because the "locally owned" store knows they have us by the balls.
Ugh.
There are many problems with gov't procurement, but they're not for the reasons you cited. Quite the opposite actually.
1. Decentralized purchasing/non-mandatory contracts. This leads to a fragmented supply base as each department or user buys whatever he/she needs. Vendors then don't have significant enough volume to offer meaningful discounts. Management also becomes an issue as no one knows how much overall $ is spent on XYZ, further reducing any leverage in negotiations. Individual departments like decentralized purchasing b/c it gives them freedom to do what they want, which isn't always in the best interest of the overall local/state/fed gov't.
2. One-off bids/contracts. Many bids are done on an ad-hoc basis, so instead of trying to negotiate a 3 year contact with price escalation clauses, it's a one-time contract or a one-year contract. Again, reducing overall volume & commitment to suppliers and reducing their incentive to lower prices.
3. Lack of standards. Stems from #1. Too much fragmentation of types/brands of products when a set of standard products would satisfy the majority of needs. Much easier to get better discounts and lower pricing when you can say to a supplier I want 1 million units of product A, B, and C, vs. I want everything in your catalog.
4. One round sealed bid process. There's no follow-up negotiation as each supplier submits their bids and hope that it's the lowest.
"Paying someone else to buy for you" is exactly the answer to this as it allows you better control and visibility into your expenditures. Most companies have centralized purchasing departments precisely for this reason.
As to the point on small business, minority, & women-owned businesses, they don't "have you by the balls." While these entities do get a preference, the preference is small. They usually get something like a 5% bonus to their final score during the bid evaluation process. If you look at the statutes governing procurement, it'll be stated there.