Bushido was real, Hagakure was written by a scribe from discussions with a holder of Bushido because before that Bushido was mostly transmitted through oral tradition. That daimyo was one to challenge useless deaths such as junji, so it’s not like he was entirely a fan of the whole thing but he probably lived by Bushido very much to the core.
Put into context that looks suspiciously like an interview for historical records and persistence in writing of an oral tradition. I would not be surprised if it was published only after the daimyo’s death because he made a vow to keep this knowledge secret, which was still common up to last century (Katori Shinto Ryu was probably one of the first schools to officially break with that and share previously secret knowledge about fighting technique and philosophy)
Now, there is romanticisation of Bushido and Samurai, but mostly from 1900s imperialism and WW2 propaganda which taints our glasses very much.
Of course any endeavour can meet an early end due to carelessness or because of not stopping and considering whether what you're doing is actually a good idea. But carelessness would probably not have been held in high regard by the samurai, and I generally fail to see a simple connection between to the samurai class becoming outdated and a preference for "quick" thinking.
I suppose one can figure out exactly how you're supposed to handle what you decided you were going to handle afterward.
Disclaimer : I am not a Samurai.
