The scarcity of bitcoin is increasing due to human error, it is estimated that around 7,800,000 BTC have been lost
[1], other reports say there are around 3,840,000 BTC
[2], this number even exceeds bitcoin that has not been mined.
[...] My question is what do you think will be the adoption and usage rate of Bitcoin then, whether it will increase or decrease? [...]
No one can resist innovation, bitcoin & crypto adoption will massively grow from year to year, in line with statistical data from Statista
[3], the lack of actual circulating supply of bitcoin because lost bitcoins cannot be a benchmark for reducing bitcoin adoption in the future. That may happen if there are not many units in bitcoin, or the minimum transfer in a bitcoin transaction is 0,1 0,01 or 0,001 BTC.
Providing a little information regarding units in bitcoin, we have bitcoin (BTC), bitcent (cBTC), millibit (mBTC), bit (μBTC), finney (finney), satoshi (sat) & millisatoshi (msat). You can visit bitcoindata.science to make conversions for each unit
[4].
Back to the discussion about adoption, because we have these units, of course a reduction in supply due to human error will not reduce bitcoin adoption in the future, even now we have LN which can make payments as small as 0.00000001 bitcoin or 1 sat
[5].
[1]
https://coingape.com/blog/approximately-7-8m-bitcoins-have-been-lost-can-they-be-recovered/[2]
https://rewallet.de/en/blog/bitcoin-statistics-2023/[3]
https://www.statista.com/statistics/1202503/global-cryptocurrency-user-base/[4]
https://bitcoindata.science/bitcoin-units-converter[5]
https://dci.mit.edu/lightning-network