And this, they told The Malaysian Insider, is because there is no one in the Malay party who is either suitable or willing to take the nation's top job.
As such, they believed the retired prime minister's latest rebuke against Najib will not see a repeat of the groundswell which made it untenable for Najib's predecessor, Tun Abdullah Ahmad Badawi, to remain in office.
"The ability to mobilise support within the party to unseat Najib now is a bit of a stretch. Najib's position is safe for now," said respected pollster Ibrahim Suffian.
Ibrahim, who is the executive director of opinion research firm Merdeka Center, said the longest-serving prime minister has "considerable influence" within Umno because of his legacy in shaping the country's political history as well as its economic development.
This latest salvo by Dr Mahathir would not "effect much political change but more of influencing the minds for discourse," he added.
As such, the onus was on Najib to figure out what was more important to him that would ensure that he kept his post, Ibrahim said.
This include articulating a vision for the country, seen as championing for a more moderate Malaysia and not allowing the country be hijacked by right-wing groups or those with narrow sectarian interests.
In lashing out against Najib's administration, Dr Mahathir had said on Monday he was withdrawing his support for the prime minister as his criticism had fallen on deaf ears.
“I have tried to give my views to him directly, which are also the views of many people who have met me," Dr Mahathir said in his popular blog, chedet.cc.
"I have no choice but to withdraw my support. This has not been effective so I have to criticise," he said, adding that Najib was no better than Abdullah.
Political observers also said Najib now needed to pull his socks up and start being a decisive leader to lead the country's reform agenda as a way to thumb his nose at Dr Mahathir's criticism.
They said the prime minister needed to show strong leadership and willingness to make hard decisions to steer Malaysia to be on track towards developed nation status.
Wan Saiful Wan Jan, who heads the Institute for Democracy and Economic Affairs (IDEAS) said while the statesman's criticism should not be dismissed completely, Najib needed to have the political will to stick to his reform agenda although there were questions over his
"Najib should be confident in his own leadership now. He should pursue the reform agenda vigorously. He should lead the way.
"Najib needs to start showing the country he is on a leadership role and is capable of making hard decisions.”
Wan Saiful believed Dr Mahathir's outburst might find some traction among Umno's rank-and-file, but this was mostly because Najib has not really gone all out to persuade members that they needed to change their mentality of safeguarding Malay rights.
Najib, he said, needed to show firm leadership that such a mentality has no place in modern Malaysia where anyone is capable of competing with anyone and the Malay community has no need of any protection.
"It is time for the current prime minister to be someone else," said Wan Saiful.
"Dr Mahathir retired many years ago, he's very nearly overstaying his welcome in commenting on current leadership issues," he said, noting that the current administration was trying to move away from Dr Mahathir's legacy and the problems associated with it.
Credited with modernising Malaysia in his 22 years of helming the country before he stepped down in 2003, Dr Mahathir was also often criticised for his unyielding authoritarian rule.
But Universiti Putra Malaysia political analyst Dr Jayum Jawan said while there was some merit in Dr Mahathir's rebuke, it could be done more diplomatically.
He also believed the ex-prime minister could make all the noise he wanted, but the prerogative was with the person at the receiving end.
"People can listen to advice but that does not mean they have to follow it."
He said Dr Mahathir's outburst would not snowball into an effect which could cause Najib's downfall.
"Umno is quite weak now. At this stage, I am not sure the people within the party are ready for any change of leadership.
"Who's the next person to take over? Getting a person that is equal or better than Najib, that's the decision Umno has to make."
Umno ministers rallied around Najib in light of Dr Mahathir's outburst, telling the former strongman to give Najib a chance.
On Monday night, Dr Mahathir had said his criticism against Najib was not personal and it did not mean that the prime minister should resign.
Instead, he was unhappy with Najib's policies and his soft approaches, which he saw did not bring any benefit to the country.
To this, Wan Saiful said: "To be honest, the right response to Dr Mahathir is 'thank you very much for the criticism, some will be accessed but today, the prime minister is Najib and no longer Dr Mahathir'.
"It is time to tell Dr Mahathir that he has retired, two prime ministers ago." – August 20, 2014.