> then either games will cost less
They don't. The prices, between MTX and multiple release versions, have gone up if anything.
> they will be better
Pretty close to unuantifiable. What quantification we have, critic scores, aren't showing any movement in the ~decade since Steam got competition (Origin, GoG, etc).
The only benefit seems to be for the shareholders and corporate executives thus far.
Also, if there are more stores it's less likely that entire categories of games will be unavailable to you (or available but worse due to reduced budgets) due to all game stores having rules banning them, and in general game stores are less likely to be able to enact policies that serve them at your expense.