Nowadays, the Post Office is now a Public Limited Company and as such is not only required to cover it's costs, but to try and maximise it's profits. Hence profits take priority over services and all the obscure little village post offices that were never designed to make profit get closed because they don't.
Not only that, they are forced to compete with other delivery companies which have been designed with profit in mind from the word go rather than service, which means that none of them have a network of delivery centres to revival that of the post office and so have lower costs and can undercut the post office while delivering the same service to the sender. The service to the recipient is less important to these companies as it's the sender that pays, so the incentive to deliver the same level of service at that end isn't there.
So, we end up in the situation where the money flows into companies focused on providing services mainly to the major financial focus points rather than an equally accessible national network and the Post Office ends up with massive financial problems and has to cut back on the amount it spends on it's services.
This obviously includes funding it's workforce, which necessarily has to be quite large to ensure the coverage we expect from the service and then we're surprised when they're not happy that there are not enough funds to support this? The fundamental thing about putting profits first, is that the welfare of the workers will be economised as far as possible.
OK, some of the services the Post Office provided can be done using other means now including other communications technologies, but as none of these can provide delivery of solid objects or somewhere you can walk in in person and deal with the majority of the day to day bureaucracies of life, the Post Office is far from being made redundant. Yet by forcing it to compete in a system based around maximising profits we're making it fall apart.
However, given our whole society is based upon profits, how can such an institution possibly exist without turning it's focus to profits itself? All in all, as far as I can see it the problem with Post Office is that it was setup with completely different objectives to those of the society to which it belongs. The question then has to be asked, which objectives were better, the ones we've got or the ones we appear to be losing?