Well Like I said I have been Watching TV since the 80's And I watch A ton of TV and I have never heard of a show that was picked up for season 1 that did not Air It's Pilot, ever hear of an Episode called Space Pilot 3,000, or How about Simpson's Roastings On An Open Fire, two of the best Pilot Episodes ever IMHO I can probably come up with thousands if not Millions more.
All A pilot really Is, Is a shows first episode In some cases That one show Is aired and based on the strength of the ratings they base weather to Pick up the show, the network that is.