Well, he at least attempted to fight back;

Before the primaries, the Governor’s Advisory Council (GAC), chaired by Tinubu, had asked Ambode to stand down for Sanwo-Olu, He defiantly refused, rather he held a press conference making derogatory remarks at Tinubu’s preferred candidate .

He also took his case to Buhari without results. He finally conceded defeat because his back was against the wall- here’s how

He faced imminent impeachment if he joined PDP

He would be impeached the very next day and automatically lose all his benefits.
36 out of 40 Lagos State house of assembly legislators are Tinubu’s boys and they all endorsed Sanwo-Olu
He has directed them to have all the impeachment proceedings ready – they just needed an excuse (defection to another party)
PDP has been waiting for him to lose (how evil) that explains why they suspended their Lagos state gubernatorial primaries, they had hoped to give Ambode an automatic ticket to run against APC come 2019.

Tinubu’s stronghold on the grass roots

"And I want to assure you. This place, we're not going to allow anybody to vote for Ambode here. If you do that, we will send you out."

This is an internal election. Imagine what their plans for the general elections are. pic.twitter.com/7XSxMVW70n

— Igala_King (@I_Am_Ilemona) October 2, 2018

377 ward chairmen from all the 20 Local Government Areas and 37 Local Council Development Areas in Lagos State waited for Tinubu’s direction on whom to endorse
These Ward chairmen according to sources had a one-on-one interaction with Tinubu’s aspirant.
They are the ones to take Sanwo-Olu’s message to the masses: the artisans, the drivers, the market women, etc.

It takes a village to wrestle Lagos from Tinubu’s strong hold. PDP might be focused winning the presidency, senatorial seats and Gubernatorial elections in other states

Saraki claimed he would show Ambode how to fight Tinubu in Lagos, but don’t forget this is transfer window –Saraki is fighting to hold his grip in Kwara state, he is also fighting for his own political survival with enemies on all sides.

Tinubu’s daughter is the Iyaloja general of Lagos State;

She controls activities in most markets in Lagos, opposition are not likely to get the necessary permits to campaign freely in the public markets- she also has the ears of the grassroots and relevant insights her father would need.

Tinubu has fought and won bigger battles

He was a Lone solider when Lagos was the only State not controlled by PDP.   Tinubu fought Obasanjo to a standstill in 2003 and held onto Lagos inspite of the fact PDP at the time had control of all the security forces, legislation and presidency.

Obasanjo also held on to Lagos allocation for 6 years. Tinubu ran the state with just Internally Generated Revenue, he didn’t owe workers and still he developed Lagos. Let’s not even get started on how he mobilized APC against Jonathan and the PDP

Right now Tinubu has consolidated his position and has his “minions” everywhere, it would be an uphill climb for Ambode. Every one really wanted Ambode to put up a good fight- I did too, it would have been entertaining to watch

Ambode should just dump APC, join a new political party (PDP or SDP), and fight Tinubu with all he's got.

If he loses, he loses. But he shouldn't lose without a fight.

After all, a Zulu proverb says: "a lion with a small penis should compensate with a big roar." pic.twitter.com/1om73UVCqp

— NafestRivers2018 (@Manlike_ED) September 30, 2018

But there is a quote that says – “Not everything in life would go your way, you must accept defeat so you can build and start again”