You have mentioned regarding the Khateeb Saheb (Imaam) who does not perform the Sunnats after the Fardh of Jumuah. It is a common trait amongst the Arabs that they attach scant importance to Sunnats and Nafls. In this regard I wish to present a few points:
Firstly, Allaah Ta`ala has ordained the Nawaafil as an expiation for the deficiencies in the Faraaidh. This is the reason why the Shariah has placed much stress on Nawaafil and Sunnan, and the Ahaadith has expounded on its virtues. It is reported in one Hadith that the person who regularly performs twelve Rakaats daily, besides his Fardh Salaat, then Allaah Ta`ala will grant him a palace in Jannat; (the 12 rakaats are) four before Zuhr, and two after, two after Maghrib, two after Esha and two before Fajr Salaat. [Mishkaat, page 103]
Secondly, regarding Sunnan and Nawaafil, people are generally divided into two categories as far as lethargy in performing them are concerned. One is found in the learned and the other in the unlearned. The error on the art of the unlearned is that they do not differentiate between Fardh and Nafl. They regard Nafl to be just as Fardh, whereas there is a difference between them of the heavens and the earth. To understand this, take the example of a person who performs Nafl Salaat the entire day, but he does not perform his Fardh Salaat, then in the Sight of Allaah Ta`ala, he is regarded as a sinner. On the other hand if a person only performs his Fardh Salaat and not his Nawaafil, then he will not be regarded as a sinner, rather he will be regarded as being deprived.
A person who keeps fast for the entire year, but he purposely omits one fast of Ramdhaan, will be regarded as a sinner. If a person fasts the full month of Ramadhaan but does not keep any fast during the year, will be regarded as being deprived, but he will not be a sinner.
Or, alternatively, the person who remains awake the entire night performing Nafl Salaat, but he misses the Fajr Salaat with Jamaat, will be a sinner, because it is Waajib to perform Fardh Salaat with Jamaat. On the other hand a person who sleeps the entire night, but he is punctual for his Fajr Salaat with Jamaat, will not be regarded as a sinner.
In short, a person who omits Fardh is a sinner, one who omits Sunnat-e-Muakkadah is liable for rebuke and censure, and one who omits Nawaafil is deprived of goodness and blessings, but he is not liable for censure. The poor masses are blissfully ignorant of the differences between Fardh, Waajib, Sunnat and Mustahab. This is the reason why they do not view the person who misses a Fardh with disdain, but they regard with contempt the one who omits a Sunnat or Mustahab. The fault of the learned is that they attach virtually no importance to Nawaafil and Sunnan, and are deprived of performing them dutifully. They understand that this (Nawaafil) is not Fardh, and therefore they are extremely lax in its performance, whereas this is also a duty upon them. The affection and proximity one has with Allaah Ta`ala is borne out by their performance of these optional Ibaadaat.
Thirdly, the narrations regarding the Sunnats after Jumuah Salaat vary. It is reported in one Hadith that the Sunnats to be performed after Jumuah are four. [Muslim / Mshkaat page 104].
In another narration it is reported that Nabi (sallAllaahu alaihi wasallam) used to go to his room after the Jumuah Salaat and perform two Rakaats. It is reported from Hadhrat Abdullaah Ibn Mas`ood (radhiAllaahu anhu) that he used to perform four Rakaats before and four after the Jumuah Salaat. Hadhrat Ali (radhiAllaahu anhu) ordered that six Rakaats be read after the Jumuah Salaat. Hadhrat Abdullaah Ibn Umar (radhiAllaahu anhu) [who reported that Nabi (sallAllaahu alaihi wasallam) used to go to his room after Jumuah and perform two Rakaats], himself used to perform first two Rakaats and thereafter four after the Jumuah. [Tirmidhi Shareef]
Fourthly, three possibilities present themselves from the above-mentioned narrations. Firstly, two Rakaats – this is the ruling of Imaam Shaafi (rahmatullahi alaih). Secondly, four Rakaats – this is the ruling of Imaam Abu Hanifah (rahmatullahi alaih), thirdly six Rakaats – this is the ruling of Imaams Abu Yusuf and Muhammed (rahmatullahi alaihima). The final ruling of the Hanafi Math-hab is on this (latter) view. Nevertheless, there is a choice of whether to first perform four Rakaats or two. Since the Arabs are mostly followers of the Shaafi and Hambali Math-habs, they will follow the rulings of their respective Imaams. For them there are fewer Sunnats and Nafls on this occasion.
Nevertheless, we Hanafis have to perform six Rakaats after the Jumuah Salaat. Even though our Nabi (sallAllaahu alaihi wasallam) loved and desired a certain action, he did not perform it very punctually and often for fear that it would become binding upon the Ummat.