that you assume "Khutbahtul Hajja" is obligatory, and since those khateebs in your locality are not opening their khutbah with this established sunnah of the Prophet, you have opted not to attend Jummah.  If this is the case, and I assume it is, it is not obligatory because the Prophet did not constantly open his sermons with it.  This was not his steady practice nor that of his Companions or authors from the scholars of Islam.  Sometimes they began with it and at other times it was left off.  Therefore if Imaams of your place and time are not using this sunnah of Khutbatul Hajja they should simply be advised that it is indeed from the sunnah of our Messenger, however not obligatory and, certainly not the bases for you not attending the Jummah prayer.  I ask Allah, Most High, to guide us to that which is pleasing to Him.

Jabir ibn Samurah says: "The Messenger of Allah would deliver his speech standing, Would sit in between the two speeches, would recite some verses, and would remind the people [about Allah]." {Reported by the group, save Imams Al-Bukhari and At- Tirmidhi.}

Jabir also related that the Prophet S.A.W. would not make his admonitions on Friday too long, but give a very short speech. {Reported by Imam Abu Dawud.}

Umm Hisham bint Harithah ibn an Nu'man says: " I learnt (suraht) "Qaf of the Glorious Qura'an" from the Prophet for he recited it upon the pulpit every Friday when he addressed the people." {Reported by Imams Ahmed, Muslim, An-Nasa'i, and Abu Dawood.}

Ya'la ibn Umayyah reports that he heard the Prophet recite, while on the pulpit: "And they cry: O Malik!…" (surat Az Zukhruf: 77). This is related by Imams Al-Bukhari and Muslim.

Imam Ibn Majah records from Ubayy that the Messenger of Allah recited: "Blessed is He…" (surat Al-Mulk) on Friday while he was standing delivering his speech.

Lastly, who is like the Prophet, who was blessed to speak few words, but convey great meaning?