You are wrong, the flight-sim, RPG, adventure and space flight games genre together with many other types of first person games were flourishing way before Doom.

http://www.youtube.com/watch?v=tm8VTZ2fyos

http://www.youtube.com/watch?v=aipGP5oAuWQ

http://www.youtube.com/watch?v=0uXZxDzqHIo

It was Elite back in 1984 that broke the mold of simple side-scrolling games.

http://www.eliteforever.co.uk/history.html

http://www.youtube.com/watch?v=ffQ_Uw55S3o

Also back in 1993 there were major technical achievements like:

Strike Commander http://www.youtube.com/watch?v=fL-ElsuJY8A

F-15 Strike Eagle 3 http://www.youtube.com/watch?v=koNyQ7J88xY

Papyrus Indycar Racing http://www.youtube.com/watch?v=VfnNo7AG7FA

Frontier: Elite 2

http://frontier.co.uk/games/older/frontier_elite_ii

https://www.youtube.com/watch?v=Yc9o_ldmlVs&t=72

https://www.youtube.com/playlist?list=PL9E1E1F7AA6193498

Which are sadly ignored by mainstream media.

Games with varying levels of sophistication were produced both before and after Doom.