funny part is.
if it costs $5000 to mine a bitcoin. but difficulty adjustmnts and hashrate competition dont make it a sure thing.
but you can buy a bitcoin for $4k and thats a sure thing. $4k guarantees you 1btc

then the OP's theory above becomes obsolete

why spend $5k mining with no guarantee of a whole 1btc,,
when you can spend $4k and guarantee 1btc and still have a bit of fiat to spare