ones upon a time they r one of the mightest kingdom in india...from maurya empire, licchvi empire etc. what a downfall.
Ironically i blame Chanakya for the demise of the Magadh Empire.
If you read Arthashastra and see the chapters on 'duties of a king', Chanakya basically makes the case that to be a good king, you must be basically an Elon Musk level of highly motivated workaholic guy, where you wake up at 5am and do state related shit till 8pm every damn day, with your 'personal time' being between 8pm and 10pm and then bedtime.
The greatest flaw in Chanakya-niti is, he doesnt understand humans. He posited a system that works, pretty much only when you have a Vikramaditya or Devpala or Rajendra Chola type of highly motivated, smart, capable king.
So we see what happens to the Magadh Empire AFTER Chanakya dies : it it the latter half of the Maurya dynasty or Shunga or the final Kanva dynasty, the pattern remains the same : 1 outta 5 emperors are actually even trying to meet Chanakya's standards, 2 outta 5 are just 'imma gonna smoke hash and have sex in my harem all the time and empire can go to hell' types and the other 2 are ' its time to be woke buddhist/jain/hindu guy who does sabka vikaas, sabka saath and state pays even more benefits and nanny-ism' crap.
Bihar's history is a cationary tale of how to piss away everything one you have everything : people do not realize this, but once Nanda dynasty expanded the Magadh Empire to directly own all of North India ( prior to the Nandas, Magadh controlled what is modern day Madhya Pradesh, Bihar,Chattisgarh & bengal as part of Magadh, everything else were vassal kingdoms of Kaushalya,Panchala,Kuru, Matsya etc) and at that point, Magadh empire had a bigger economy, population base and military than that of the Sakhamani Persian Empire that Alexander took down.