Re: Private enterprise.
You highlight another example of exactly the same. The private sector ripping off the tax payer because they are represented in these cases by the most gullible of all fools - a gullible inexpert person with a pile of someone elses cash.
It is tricky because there aren't many ways out...
a) You could try consultants that are supposed to know the business - i.e. IT - and can properly advise, but how do you know which consultants can, and whether they are advising you correctly on getting a back hander (bit like when your pension adviser said to buy a private pension thats now worth squat - but they still got their commission).
b) You could try centralized purchase done by experts employed by schools/nhs/who ever which are buying on a scale that could force huge discounts, but we know from bitter experience that this also leads to the doing of favours for friends, of buying from huge suppliers in preference to local smaller business.
c) You could try paying the people involved a little more and insisting that they spend 'their' money on the goods - saying they can keep the difference between what they spend and what they buy... but this can lead to the purchase of cheap but shoddy, insufficient amounts, etc. without actually saving the tax payer a penny.
Or, when a company is clearly responsible for shafting the tax payer you could black list the company bosses so that if they are ever involved with any other company that they never get a government contract again, or in the worst cases of clearly poor professional conduct (such as selling a 'support contract' for the price of half a dozen replacement PC's) you could jail them for fraud. I know my local school ignored my pleas for common sense and bought a couple of dozen laptops and support contracts. Each laptop with its support contract cost them more than the price of 5 in the local shop and about 10 perfectly suitable desktops (the laptops were chained in the 'computer lab' and never moved). But the 'support contract' made them feel 'safe'.... the fact they could have just thrown the broken machine in the bin and replaced it didn't seem to occur to them as the best route to travel.