Some people appeal to the below hadeeth from the Prophet (peace be upon him) to argue that Shirk cannot become a major problem for the Muslim Ummah:
مَا أَخَافُ بَعْدِي أَنْ تُشْرِكُوا، وَلَكِنْ أَخَافُ أَنْ تَنَافَسُوا فِيهَا
By Allah! I am not afraid that you will worship others along with Allah after my death, but I am afraid that you will fight with one another for the worldly things." [Bukhari]
However, this hadith can be understood as referring specifically to the Sahabah in that they will not apostatize en masse after the Prophet (peace be upon him) passes away, as suggested by scholars like al-Qurtubi (656 A.H.)[1] and Ibn Hajar al-Asqalani (d. 852 A.H.).[2]
However, the bulk of scholars who commented on this hadith said that this refers to the entirety of the Ummah, such as an-Nawawi (676 A.H.),[3] Zayn ad-Deen al-Iraqi (d. 806 A.H.),[4] Shams ud-Deen al-Birmawi (d. 831 A.H.),[5] Ibn Hajar al-Asqalani (d. 852 A.H.),[6] Badr ud-Deen al-Aini (d. 855 A.H.),[7] al-Suyuti (d. 911 A.H.),[8] al-Qastalani (d. 923 A.H.),[9] Zakaria al-Ansari (d. 926 A.H.),[10] al-Fattani (d. 986 A.H.),[11] Mulla Ali al-Qari (d. 1014 A.H.),[12] etc. Thus, this hadith does not discount the possibility that some from the Ummah would fall into the Shirk. This is especially the case when another authentic hadith states that a time will come when some from among this Ummah would fall into Shirk:
لا تقوم الساعة حتى تلحق قبائل من أمتي بالمشركين وحتى يعبدوا الأوثان وإنه سيكون في أمتي ثلاثون كذابون كلهم يزعم أنه نبي وأنا خاتم النبيين لا نبي بعدي
The Hour shall not be established until tribes of my Ummah unite with the idolaters, and until they worship idols. And indeed there shall be thirty imposters in my Ummah, each of them claiming that he is a Prophet. And I am the last of the Prophets, there is no Prophet after me. [Tirmidhi & Abu Dawud]
When we say that “some” of the Ummah can fall into Shirk, what does “some” mean? Five percent? 10 percent? We cannot say for certain. We know that immediately after the Prophet (peace be upon him) died, thousands reneged on Islam and followed false prophets, returning to their old paganistic ways. If we assume that the Ummah at that time was roughly estimated to be 200,000, then several thousand apostatizing would be equivalent to tens of millions falling into Shirk today, given how much the Ummah has grown. It is hard to say as the Shari’ah is silent about this matter. This is probably why many major scholars over the centuries had no problem acknowledging that Shirk was a serious problem in the Ummah, as can be seen here Non-“Wahhabi” Quotes on Venerating the Dead.
Recommended Reading
Sultan al-Umayri, al-Maslak al-Rasheed, vol. 2, page 619 onward.
[1] He said in his commentary on Saheeh Muslim:
و(قوله: إني والله لست أخشى عليكم أن تشركوا بعدي) يعني: أنه قد أمن على جملة أصحابه أن يُبدِّلوا دين الإسلام بدين الشرك. ولا يلزم من ذلك ألا يقع ذلك من آحادٍ منهم، فإنّ الخبر عن الجملة لا يلزم صدقه على كل واحد من آحادها دائمًا، كيف لا؟ ! وهو الذي أخبر بأن منهم من يرتد بعد موته
[2] He said in Fathul Bari:
وأنَّ أصْحابَهُ لا يُشْرِكُونَ بَعْدَهُ فَكانَ كَذَلِكَ ووَقَعَ ما أنْذَرَ بِهِ مِنَ التَّنافُسِ فِي الدُّنْيا
[3] He said in his commentary on Saheeh Muslim:
وفِي هَذا الحَدِيثِ مُعْجِزاتٌ لِرَسُولِ اللَّهِ صَلّى اللَّهُ عليه سلم فَإنَّ مَعْناهُ الإخْبارُ بِأنَّ أُمَّتَهُ تَمْلِكُ خَزائِنَ الأرْضِ وقَدْ وقَعَ ذَلِكَ وأنَّها لا تَرْتَدُّ جُمْلَةً وقَدْ عَصَمَها اللَّهُ تَعالى مِن ذَلِكَ وأنَّها تَتَنافَسُ فِي الدُّنْيا
[4] He said in Tarh al-Tathreeb:
وإنِّي واَللَّهِ ما أخاف عَلَيْكُمْ أنْ تُشْرِكُوا بَعْدِي) أيْ مَجْمُوعُكُمْ وإنْ كانَ قَدْ يَقَعُ ذَلِكَ لِبَعْضِهِمْ)
[5] He said in al-Laami’ al-Sabeeh:
وفيه: معجزاته - ﷺ -: مُلك أمتِهِ خزائنَ الأرض، وعصمتُهم من أن يَرتدُّوا جميعًا
[6] He said in Fathul Bari:
قَوْلُهُ (ما أخافُ عَلَيْكُمْ أنْ تُشْرِكُوا) أيْ عَلى مَجْمُوعِكُمْ لِأنَّ ذَلِكَ قَدْ وقَعَ مِنَ البَعْضِ أعاذَنا اللَّهُ تَعالى
[7] He said in Umdat al-Qari:
قَوْله: (ما أخاف عَلَيْكُم أن تُشْرِكُوا) قيل: قد وقع بعد رَسُول الله ﷺ، ارتداد لبَعض الأعْراب. وأجِيب: بِأن الخطاب للْجمع فَلا يُنافِي ارتداد البَعْض.
And:
قَوْله: (ما أخاف عَلَيْكُم أن تُشْرِكُوا بعدِي) مَعْناهُ: على مجموعكم، لِأن ذَلِك قد وقع من البَعْض، والعِياذ بِاللَّه تَعالى
[8] He said in al-Tawsheeh:
ما أخاف عليكم أن تشركوا) أي: على مجموعكم، لأن ذلك وقع [من] البعض)
[9] He said in Irshad al-Sari:
أي: ما أخاف على جميعكم الإشراك، بل على مجموعكم، لأن ذلك قد وقع من بعض
[10] He said in Minhat al-Bari:
ما أخاف عليكم أن تشركوا بعدي) أي: أخاف على جميعكم الإشراك، وإلا فقد وقع من بعضهم)
[11] He said in Majma’ Bihar al-Anwar:
ما أخاف عليكم أن تشركوا- أي جميعًا وإلا فقد وقع من بعض
[12] He said in Sharh al-Shifa:
مع أنه لا يبعد أيضا عن المراد قوله (وإنِّي واللَّهِ ما أخافُ عَلَيْكُمْ أنْ تُشْرِكُوا بعدي) أي جميعكم
You mentioned ibnHajr al Asqalani for both the restricted and unrestricted application of the Hadith