of the industry practice of price gouging on replacement batteries.
Their new line of 18v tools all use the same battery, and replacements
are available for $39 for TWO new batteries. I believe they have also
pledged to keep the same battery format for any new 18v tool they
bring out.

So Ryobi doing what everyone else has been doing for 10 years is somehow
new?
Any decent brand has standardized on battery connector for the same voltage
across all their tools. My 9 year old Makita drill battery will plug in
the same drill I bought my father last year as will it plug into my father
in laws makita drill he has had for longer than I. All the other tools I
have bought use the same ones as well. This is one example, the other
brands do the same. The only brands that haven't done this up until now
have been ryobi and sears and the other toy tools.