More importantly, the bottom line is that the government needs tax revenues. If you want the gov't to cut spending, that is a totally different topic. If you allow the government to exist in any way/shape/form, it needs money, and if they can't get sales tax, they will just increase your real estate taxes instead until they can cover the difference, or any number of alternative tax revenue avenues. Heck, abolish state sales taxes entirely for all I care, it's a regressive tax anyway, just make sure that whatever tax is raised in its place is applied fairly. One way or another, they will collect tax. If you don't like it, then fight spending until they don't have to collect tax. But wanting all the spending, while denying the necessary tax revenues is fiscally irresponsible.
If by government, you mean State Government then yes, they do rely on sales tax. But most (if not all) states that collect sales tax ALREADY have a mechanism in place to charge sales tax on out of state purchases directly to the consumer. It's called a 'use tax' and states should be using THAT to collect the sales tax due. Do you know how many businesses I deal with that don't pay the use tax when they buy stuff from Amazon? States should have focused on collecting this tax instead of wishing for some magical solution that would drop revenue in their laps. So, now instead of auditing state citizens, states are going to have to create centralized departments to deal with basically every online company in the entire country and start auditing them. Sounds like a much more expensive solution to collect what should be the SAME amount of use tax revenue.