14 should be the max number of schools for ALL conferences who have or are almost to that limit. If over 16, then the conference-play scheduling format would be difficult.
This is obviously not saying that conferences MUST go to 14, but only they MAY NOT go past 14. For me the next question is where do the current conferences go to for expansion?
B1G: 14 - done
SEC: 14 - done
ACC: 14 (15ish) - done
CUSA: 14 - done, but will probably be a target of other conferences so expansion may be wanted/needed, would look to SBC or FCS upgrades
MAC: 13 - may pick up James Madison, may lose Massachusetts, would look to CUSA (Marshall? Western Kentucky? Old Dominion? Charlotte? Middle Tennessee St?)
PAC: 12 - would not likely pick up Texoma-4, would probably sit at 12, would look to MWC if wanted to expand
AAC: 12 - will probably be a target of other conferences so expansion may be wanted/needed, would look CUSA and MAC for targets
MWC: 12 - would probably sit at 12, but would look to BYU and schools in CUSA (UTEP? UTSA? Rice?) and AAC (Houston? SMU? Tulsa?)
SBC: 11 - will likely go to 12 with an FCS upgrade, will likely be picked by CUSA a few more times, then would look to FCS upgrades ----- with all the upgrades recently, they might as well make 3 subdivision in division 1 football (Power, Bowl, Championship)
XII: 10 - if 14 is a cap, the XII is here to stay, would look to AAC first for expansion (Cincinnati? Connecticut?) then to BYU/MWC expansion