Not only in cricket, take example of professional boxing, one of the most physically demanding sports. I just came to read on news that Floyd Maywether defeated some 20 odd years old MMA fighter in an almost one sided match.
The problem is not about the age. Its just that we want to see heroes fall from grace and the best way to do so is blaming their age. Have their side in their rough patch, stand strong with them. Always remember form is temporary, class is permanent.
When social security was developed, it was questioned whether the Federal government had the authority to order State and local government units to participate in it, so in order to increase the chance that social security was approved, State and local government units were exempt from mandatory participation in SS. However, they were required, if they chose not to participate in SS, to create retirement plans for their employees, in which the benefits equaled or surpassed the benefits provided by SS.
Many state and local retirement plans allow employees to retire and withdraw funds after relatively few years of employment, and at ages much younger than required for eligibility of SS retirement benefits, AND many allow employees to collect from more than one pension plan.
Many people are misinformed about SS and other government pension plans, believing that the amounts contributed by themselves and their employers completely fund their benefits; when in fact, they are “defined benefit” plans, and the majority of individuals collect benefit amounts greatly exceeding their contributions. In reality then, most SS and pension money received after the first few years of retirement is more accurately compared to “entitlement programs” such as welfare.
The politicians are elected by people and as long as people think that they are of sound body and sound mind and can represent their cases and causes properly, they keep electing them. As for as civil servants and other professionals like engineers, doctors etc working in government offices is concerned they have to physically exert and travel. That type of high efficiency physical effort can not be undertaken beyond a particular age. That is why retirement age is fixed in most of the nations.
For politicians it is different. The age matures them. They develop more following as years go by. Their main focus is on speaking on issues on public platforms, in assemblies, in parliament, organise protests, oppose other political parties and so on. Even if they are old they can be taken to a platform on a wheel chair and made to speak.
The elected persons are to be re-elected to remain in office after expiry of their term unlike service holders. So their tenure is fixed till their term ends. In case of service holders, it is a contract where the fixed tenure is specified. There is no scope for re-employment unless the appointing authority appoints the retired person in another post. For example retired IAS and IPS officers are reappointed as Governors or Election Commissioners in India.
However, in the USA the tenure of the President is two terms only. He cannot be re-elected after that to the high office. In many countries of the World the monarchs occupy the throne life time as in the case of the British crown. Recently China abolished fixed term of its President. Thus he cannot be removed from office except by resignation, death or military coup. Thus practices differ from country to country.