I'm inclined to be more optimistic! This site may give the impression of a great deal of bad practice, but people are most inclined to ask questions when they are faced with a problem. Indeed, the main reason for creating this site was that individual councillors and citizens have few resources to call upon when they want to understand how best they can push a council into better behaviour. Entrenched councils tend to fob people off with technicalities and so rebels need sources of knowledge to respond effectively.
Up and down the country, there are many town and parish councils that operate lawfully and constructively. Many clerks are knowledgeable, or seek advice when needed. Many councillors work selflessly for the good of their communities. Budgets may be relatively small, but local councils can have real benefits in promoting and supporting local activities. They can provide some local services very efficiently.
It is true that having an effective local council relies on there being people who are willing to make the effort to be councillors or to press their council to act well. Even when there was a formal standards body for local councils, enforcement relied on local action. If nobody cares what their local council is doing, then it shouldn't be too much of a surprise if it goes off the rails.
However, if there are people who are willing to be active, there are plenty of ways to achieve results. One route is the local press. If you come up with detailed evidence of problems such as misleading minutes or refusal to respond to citizens, then there is every chance of getting coverage. Simply spreading the word that there is a campaign for higher standards in the council can also be effective. I have personal experience of councillors resigning because they became concerned about the low esteem in which they were held by their neighbours.
Incorrect procedures in the handling of casual vacancies, both in relation to declaring a non-attending councillor disqualified and in procedures for co-option, should be referred to the monitoring officer who should act. The following of proper democratic procedures is their responsibility.
The other vital route is the auditor. There is an auditor for every local council, even if there is no audit on account of the latest regulations for smaller authorities. The auditor has wide responsibilities. It is not a purely financial role, but involves assurance that the council takes decisions lawfully, records them correctly and spends money in accordance with those decisions. The audit fee is very small, so you cannot rely on the auditor to find problems, but you can expect them to take action if problems are reported to them.
The audit process has to be inexpensive, otherwise it would be out of proportion to the money being handled by local councils. The whole process relies on councillor audits and the report of the internal auditor (who must be independent of the council). The external auditor forms an opinion based on information provided to them. But if you have evidence that the internal auditor is not independent or that the records do not reflect lawfully taken decisions or any similar defect, and can report it to the external auditor, they should take action.
Indeed, individual councillors could find themselves with a financial liability if the council is taking decisions unlawfully. This is another point that can be used in a publicity campaign to raise standards.
So, if people are unwilling to do anything or are not prepared to put their names to actions to raise standards, then you are inviting poor quality in your council. But if there is a pool of people willing to be active, then results can be achieved, sometimes surprisingly quickly.