Please explain why Blu-ray is only marginally better than DVD on my display.

[Jar Jar Stinks]

I can't notice a huge difference between the DVD and Blu-ray of the same movie. As a test, I've played both discs of several movies simultaneously, switching back and forth to view the same scenes. For example, "Planet of the Apes" (1969) looks virtually the same. Even "Empire Strikes Back" wasn't greatly different.

Here are my questions:

1. Could it be that when the aspect ratio is too wide, the benefits of the higher resolution aren't as noticeable?
2. I sit about 10 feet from the screen. Is my display too small?
3. Is my DVD player and/or my TV doing such a fantastic job upscaling that differences between the DVD and Blu-ray are not that evident?

Here's my setup:

• Display: Panasonic VIERA TC-P42ST30 42-Inch 1080p 3D Plasma HDTV.
• DVD Player: Philips DVP5990 DVD/DivX player with HDMI output and 1080p upconversion
• Blu-ray Player: Panasonic DMP-BDT110