Usually, government projects are only for a small part of the population and isn't going to do much good for the majority. When it comes to government projects the main goal is to make it seem as cheap as possible so there won't be much opposition to it. Once the project started the costs are going to balloon and in there much anybody else can do, because stopping the project would make it seem like a fail and lead to a public outcry. I remember reading about a study that found out that almost all the large-scale government projects in the western world ended up over budget. It's so much easier to make decisions with money that you don't own and I wish there was more oversight over how inefficient politicians are with tax payers’ money. The problem is that most people are not really interested in politics in detail and will accept all the excuses the politicians offer for their high spending.
That's true that majority of tax payers are willing to pay more taxes then to go and ask government about money embezzlement. The main reason is that you need to have a strong background with links everywhere to step into politics, the weaker ones are easily kicked out by old politicians. It is seen that politicians after gathering money usually left the country and keep there assets in treasurers of Swiss banks. The condition is better in developed countries bur worse in underdeveloped countries.