Why are there 39.5K+ different so called Christian denominations when God commanded "Let there be no divisions among you" (I Cor 1:10)?

Each cult wants a cut of the pie[money].

Nothing causes more division than religion.  The greedy start new churches for the cash.  Money is why that church is there.  It's only function is to gather money from poor people.

Obviously he was referring to all those OTHER divisions, not the one true faith that happens to be the  one the reader follows.

Interesting thing is that if you get to know any one of the members of any one of these denominations, odds are extremely high that you will find they do not actually obey anything Jesus said.  So, it's not like they just happen to fail to obey the "no divisions" command.  They just don't obey anything.

Paul appealed to Christians in The Problem Church of the 1st century. Corinth was a divided congregation. Read all of that letter to them, to see they were riven with awful things that ought not to have been. He had to command them to put out a brother whose sexual immorality even shocked the pagans. Others were claiming to be followers of this apostle, or the next one, instead of following only Jesus. They had law-suits against each other! Read the entire letter! But then read the follow-up letter, where he commended them for having restored the repentant, formerly immoral brother, when the congregation was much less divided.

You cannot use that one verse out of context. He wrote elsewhere to chastise believers for not maturing in faith and understanding. He warned about certain men who had crept into the congregations as wolves in sheep's clothing. The Christians back then were no more 'perfect' than they are now, though it's certainly far worse these days as splits have turned into chasms with those wolves in sheep's clothing.

To keep the balance, remember that most of the denominations are agreed on the basic, fundamental doctrines of the Christian faith, and many have fellowship with the others. God will hold to account their leaders if they fail to tend the flock under their care properly. Finally, Jesus was speaking of the love for Christ and God that would identify Christians - perfect LOVE is what identifies them. And such ones have the indwelling Holy Spirit, irrespective of any denominational tags they might (or might not) have.

Blame Luther.  He established the precedent of anyone unhappy with the status quo leaving and starting his own church, whether or not he's in any way qualified to do so.

None of them will obey Mat. 5 ; 48 GT . And so they each pick a scriture that is unique and easier to follow 

Usually for one of the following two reasons:
- irreconcilable disagreement concerning doctrine
- irreconcilable disagreement concerning leadership

But on several occasions there is another reason. (Note: using "state" in the sense "government".)
- denomination is (or: was) a state religion, and so same church in any other state must of necessity be a separate denomination, a denomination of a different state
- state allows (or: allowed) only specific, state-controlled denominations to practice in the state, and so denominations that evangelized in that state had to set up a separate denomination to be able to operate legally in that state

Because people have caused the divisions due to their interpretations of scripture. Everyone has their own interpretation. What needs to be done is to find common ground instead of "being right".

Here the answer: https://www.jw.org/finder?wtlocale=E&docid=502015171&srcid=share