What happens if the population increases and there is a need to increase government budgets to provide programs and services taxpayers need and/or want?
Not a problem. Elected officials will simply need to identify the new programs and services, identify the costs and ask taxpayers to approve the increased spending. If the taxpayers want the programs and services they will approve the increased budgets and if not they will choose not to do so. This is what true participatory government is all about, what the citizens want, not what the government wants.