They have been investing in the parks and elsewhere. See DTD for example. TWDC is blessed to have a CEO who knows how to win by not putting the cart before the horse. So investing in infrastructure was necessary to the long term financial viability of WDW. So that is what has happened. The fun stuff will follow. See Pandora for example.
The two don't have to happen one after the other. Infrastructure expanded massively under the good days of Eisner, but so did 'the fun stuff'. If you aren't aware of how poor today's investment is compared to yesterday, take a look at a seven year period from 20 years ago (for my own sanity I'm ignoring attraction remakes and DVC hotels).
1988: New land at MK (Mickey's Birthdayland), brand new pavilion at Epcot (Norway), fireworks show at Epcot (Illuminations)
1989: MGM-Studios - an entire new park, a *massive* expansion of Downtown Disney (Pleasure Island), a brand new Future World pavilion with several attractions (Wonders of Life), a game-changing water park (Typhoon Lagoon), and a new parade at MK.
1990: Two deluxe resorts (Yacht & Beach), two convention hotels (Swan & Dolphin).
1991: A moderate resort (Port Orleans French Quarter), new MK night parade (Spectromagic) and a new day parade at MK.
1992: Another moderate (Dixie Landings), Aladdin parade at MGM, a new day parade at MK
1993: OK, I can't think of much that happened then!
1994: An entire water park (Blizzard Beach), a value resort (All-Star Music), Lion Kong parade, massive expansion of MGM (Sunset Boulevard), and a new day parade at MK.
Counting a new land or pavilion as a large expansion, and counting parades as shows, I think that gives the following:
= 3 whole new parks, 9 shows, 8 hotels, 5 large expansions (with around 7 attractions between them).
You don't do all that without building a lot of infrastructure along with it.
Now let's compare recent years, shall we?
2008: Toy Story Mania
2009: American Idol experience
2010: Magic, Memories and You projection show
2011: Pixar Pals parade at DHS
2012: New Fantasyland, Art of Animation Resort
2013: MyMagic+
2014: Seven Dwarfs Mine Train, and a new day parade at MK.
= 3 shows, 1 hotel, 1 large expansion (with 4 attractions), 2 other new attractions
Or, for arguments sake, let's take a 7 year block ending with what we know, Avatar.
2011: Pixar Pals parade at DHS
2012: New Fantasyland, Art of Animation Resort
2013: MyMagic+
2014: Seven Dwarfs Mine Train, and a new day parade at MK.
2015: ...
2016: Massive Downtown Disney makeover as Disney Springs Mall.
2017: Pandora opens at DAK along with night show
= 4 shows, 1 hotel, 3 large expansions (with around 6 attractions between them).
So you see, Iger has not exactly been generous with the purse strings in recent years compared to his predecessor.