Just throwing out a few suggestions here as to why Microsoft would do this:
- They have geared their default to be best possible OLAP performance (less page reads with a fill factor of 0/100)
- They are assuming that
INSERT
ed data will most likely be at the end of the table, making the extra space per page useless - They are assuming that typically
UPDATE
d data will not lengthen row data very often, causing a page split
This is just guessing here. The only people that can really answer that question accurateaccurately is the SQL Server team themselves.