Although it is simplied model, while it provides basic thinking about it.
My question is is there other popular model/formula about it ?
I dont think there would be a model/formula about it yet here on cryptospace where people do only refer on whats being written on coinmarketcap.com when it comes to
its total market capitalization which would signify its demand and this isnt the accurate one since OTC trades arent really being tallied nor being included.
BTC price is the average total on where bitcoin is being traded.
There is really no accurate formula for the bitcoin price. Spare yourself in knowing one as there is nothing that you will find. The formulas the OP presented are just basic equations to get the approximate price. But looking for an accurate one, nope. There are a lot of factors in play here, aside from countless exchanges involved, the happenings or situations surrounding the use of bitcoin or crypto are immeasurable.