The rule which I have underlined has never been the case. Each league has had the option of choosing how it selects its automatic qualifier, either by regular-season play, or through a conference tournament; the Ivy League still chooses its regular season champion for its qualifier, and the Pac-12 and B1G have also done so in the past, but most leagues use a conference tournament.
The rule which I have bolded, regarding a minimum membership and years playing the sport together is indeed a thing which is in force. Generally speaking, any conference seeking an automatic bid to the NCAA tournament in any sport requires meeting a "six for two" standard (i.e. the conference must have had at least six teams, who have played together for two years). For men's basketball, the requirements are a bit more stringent: at least seven teams who have been NCAA Division I members for the previous eight years, and who have played as a group for at least the last five. This is rule 31.3.4.5 in the D-I manual.
BUT, any conference that has previously met the standard for an autobid receives a two-year grace period (rule 31.3.4.5.1) as long as they maintain at least six members.
So, what will happen on July 1, 2015, when ten current Big East members are scheduled for withdrawal, pending any agreements to be made regarding an earlier exit: The Big East will possess 9 "core members" (read: institutions which have been in the division for at least 8 years): Connecticut, Cincinnati, South Florida (the three of whom have been full members for at least five years); Temple, Central Florida, Southern Methodist, Houston, Memphis (the five of whom will join in 2013-14; and Tulane (due to join in 2014-15). Only three of those members (UConn, Cincy, USF) will have played basketball together for more than five years, but since the league previously had an autobid, they will at that point receive a waiver for the 2015-16 and 2016-17 basketball seasons. So as of the start of the 2017-18 season, the Big East will have had 8 teams (all but Tulane) who have played hoops together for...four years. At that point, I expect a waiver to be applied for and granted.
Incidentally, this does mean the new "Catholic Conference" will be eligible for an automatic bid starting on that date. They will have 7 core members, who have played at least five years in conference competition with each other (the rules are *oddly* nonspecific about the conference competition needing to be under the auspices of the conference seeking the automatic bid).