Lets see. If what you say is true. Then BAL's days are numbered because without Indian support they are nothing..A little border tension with China will cause Delhi to loosen its grip on Dhaka and BAL. This will also weaken BAL itself or BAL's very top leadership.
This is how changes may come to BD politics. But, which of the parties will substitute BAL no one really knows unless the time comes.
However, changes at the top may come from within BAL also and it will get more popular than now.
Even if BAL changes their top leadership ( highly unlikely) they wont survive politically. Change is actually a double whammy suicide for them as Change will not raise their popularity in the country ( no will will forget the misdeed of the last 12 years easily), but they will lose their main sponsor ( India). Highly stupid and unlikely move. What BAL should have done is distance itself from India from 2019 onwards. But now it is just a matter of time. But unfortunately they are going.
Either way coming months will be very revealing towards the Indian designs for BD.