Having had interest for bitcoin among all altcoin, I tried to imagine if the price of bitcoin is reduced to atleast 80% so that It can be affordable, and before this is done a proper warning is sent to all the users and holders so that they can sell before time to avoid lost on their part and buy back when it is stable and relatively cheap.
Value is different than price, and value decides price.
Bitcoin adoption and value as well as price growth are very sustainable with time since 2009 because Bitcoin has its value that has been becoming more recognizable by people globally and even governments.
You can not devalue Bitcoin just because you want to make it more feasible to buy and own for more people. If a future Bitcoin is like what you want, its value is lower and there will be less people who have interest in Bitcoin investment. It won't help to increase Bitcoin adoption and trading volume, then price will be affected and dumped.
There are thousand altcoins that are cheap but intelligent investors don't want to invest money in those altcoins. Bitcoin does not need to become those useless altcoins by any devaluation proposal.