Implementing both F2P/Sub is also an option

[TheRogueX]

This right here. Patches would definitely not happen every 3 months anymore, it's impossible to budget on a F2P and make
any kind of road map. You don't know if you are going to have to fire staff or cut back on resources month-to-month.

Wouldn't be a fun time if that had to happen, you're looking at possible 6-8 months for 1 patch if not enough people play.

I know of three games off the top of my head that prove you wrong:

Lord of the Rings Online (hybrid F2P/Subscription model)
Champions Online (hybrid F2P/Subscription model)
Star Trek Online (hybrid F2P/Subscription model)

LotRO has had 4 FULL-SIZED expansions since it went F2P and numerous smaller free patches in between.
Star Trek Online gets new Seasons with new content constantly (it also recently got a full-sized expansion with an entirely new faction and restructuring of the original two factions), and Champions Online gets new 'Issues' with new content.

Oh, and I just thought of a fourth: The Secret World.

You can have a F2P game that doesn't sell actual gear in its market. Cosmetics, new mounts, collectible items, etc can still make a crapton of money.