Yes Bengalis compromised in a lot of different things only to keep the Pakistan united despite hardship and horror. They accepted Urdu (infact learned urdu), accomodated and accepted W. Pakistanis in the lucrative jobs, allowed w. pakistani and biharis to dominate businesses. They also faught for Pakistan. But the question is how much reciprocacity W. Pakistani shown in return. Could you find a single W. Pakistani who ever tried to learn Bangla or even introduced that to any of the W. Pakistani curricular even though Bengali was granted as one of the State Language.
You have to go deep not just a show off.
PS: As you mentioned, If Pakistan still united, then Bengali would have been still the majority language as it would have been learned by more and more people, like Hindi in India which is still growing. Again only if that was meant to be the state language not an apeasing language to certain groups.
I just want to clear somethings, you may not agree but its ok.
I am from Lahore, my mother language is Punjabi. Urdu is our state language. Before partition Urdu was the sole communication language all over sub-continent. There was a reason for that and quite a good one.
Urdu is a turkish word which means "Lashkar". When mughals ruled India, their mother and official language was Persian. In their army soldiers belonged to all across sub-continent. There were Rajputs, Gorkhas, Sikhs, Afghans, Persian, Turkish, Marhattas to name a few. A new language named urdu was born bearing common words from all these languages. So whether one is a Bengali or Tamil or Pathan or Punjabi, its the only language in sub-continent which everyone can understand and communicate.
So, if Quaid-e-Azam has declared Urdu a national language, that was the main reason. If United Pakistan has been in existence today, Bangalis would also have 2 languages. Urdu as official, Bengali as mother. And being a Pakistani Punjabi, i can tell you with full faith that there would have been no dangerous to Bengali. Even in Pakistan, all local languages are alive. People speak them, write in them, do poetry in them.
One more thing, you can understand my point by just one example and that is of Bollywood. Why would you think that all bollywood films are made in Hindi? Its because its the only language which everyone all across South asia understands.
And Hindi is no language. Its a trick by Indians to brand Urdu as their own. They knew very well from start that to keep India united they need a universal language like Urdu. So they take urdu with Sansikrit script and change many words of it with sansikrit and hijacked a language. Otherwise its a nite-mare for Indians to select a language from at least 20 major lingual groups.