Games are poor relations to ring-tones: are they? 5-20% of the mobile personalisation (i.e. ringtone and logo) market sounds pretty meaty to me.
The ringtone and logo market is massive and mature: it's routinely advertised through widespread broadcast media, it's supported by every handset on the market today (and most that have been on the market this century) and it's been at least 5 years in the making: of course it's bigger. This doesn't imply any failure of the mobile gaming market.
And mobile games need more realism? I don't think this is what's holding them back: look at the Gameboy Advance. That's a mature gaming platform that's been around for years, and I don't see much in the way of 3D there... but it's nonetheless been successful.
What mobile gaming needs is.... duh, more mobile games! By that I mean games designed for a mobile phone (i.e. one-handed use, dip-in and dip-out play, networked), not dull conversions of yet another arcade classic which only has nostalgia value for the 30somethings and older like me. Look at what kids these days think of these games - of course I can't find the link now, but I have posted a story in the past where kids were shown these "arcade classics" and found them routinely boring.