* Company A has 1M in capital, and builds an in-house database with 1M$ of dev salaries. At the end of the year, company A is worth 0$ because they spent all the money.
* Conpany B has 1M in capital and buys (wholly and exclusively) a custom database for 1M$. At the end of the year, Company B is worth about 1M$, because they have 0$ in cash and a 1M$ database.
Clearly there is an issue there, and the only way to make the two situations equivalent is to treat software development as a capital expenditure which is what it is.
assuming you meant revenue and income, your example actually perfectly illustrates the problem. Company A has $1MM in revenue, spends $1MM on SE salaries and is taxed on $800k income. Company B has $1MM in revenue, spends $1MM on some AWS db service and has no income to be taxed on.