And most teams that bring in a ton of players get relegated. They use a number of examples of teams that barely sign anyone of being promoted, and end up staying up, compared to teams that sign a lot and end up going down.
Either way, stability is the key seems to be the main message.
http://www.planetfootball.com/in-depth/investigating-arsene-wengers-claim-three-signings-many/
An interesting read for anyone that thinks we need a massive overhaul.