I think a better explanation is that taxes on revenue favour vertical integration.
Imagine a product that requires building widget A, then turning that into widget B, then turning that into widget C. If we have the following companies:
C: revenue $6m, purchase costs $4m, other costs $1m
B: revenue $4m, purchase costs $2m, other costs $1m
A: revenue $2m, purchase costs $0, other costs $1m
then taxes are paid on $12m.
If we instead have:
Alphabet: revenue $6m, purchase costs $0, other costs $3m
then taxes are paid on $6m, even though the same amount of stuff is being made with the same efficiency, same profits, etc.
Whether this is relevant for tech giants is another matter. Software tends to be quite vertically integrated (financially speaking, at least).