Yes this was definitely pre-Cars land, so DCA was easily a half day park even with the Aladdin show and returning for WOC and ElecTRONica (at the time). Plus DCA had the shorter hours that made it possible to slip in things at
Disneyland Park before and after. I don't think it'd be really possible this summer. And for full disclosure the Matterhorn was down as well at the time. And yeah, food and sleep were the two things that really got pushed to the side to make it happen.
Excuse my analytical side, but I find your claim so hard to believe I had to crunch the numbers.
Take two weekend days or high season summer days - which you must if you want to do "everything" - otherwise shows are not running - and you will have DL open 8AM-Midnight. So 16 hours per day. Over two days that means 32 hours in the parks.
Seeing all shows and doing other necessaries takes the following amount of time - assuming a minimum time to queue into each viewing area and just see the show without necessarily a good view:
1 hr - WOC
1 hr - F!
0.5 hr - fireworks
1 hr - Aladdin
0.5 hr - Soundsational parade
0.5 hr - DCA night show (ElecTRONica, Mad T Party, whatever)
0.5 hr - see some street shows at DL
0.5 hr - see some street shows at DCA
0.75 hr - Billy Hill and the Hillbillies
0.5 hr - Jedi Training Academy
0.5 hr - Princess Fantasy Faire
0.25 hr - Pixar Play Parade
2 hr - Lunch and Dinner over 2 days, time to queue, order and eat - very fast
0.5 - Quick personal breaks to the loo
The above totals to 10 hrs, which leaves 22 hours for rides. My last count has 70 rides at DLR. 70 rides over 22 hrs is less than 19 minutes per ride. That is time to walk to each ride, queue each ride, load each ride, ride each ride, and exit each ride. And it would have to be on busier weekend days in order to see the shows.
Some rides are short like PP for maybe 2 minutes. Some are long like POTC (16 minutes) and Mark Twain. I would say it is fair to say that each ride on average takes 9 minutes to board, ride and exit.
Of the 19 minutes per ride that leaves 10 minutes to walk to each ride and wait in each queue.
In between days 1 and 2, let's day you are at the GCH or another real close hotel. You should be able to be to bed by 12:30AM and will need to wake up by 7AM in order to get to the gates by 7:30/7:45AM and be one of the first into DL to ride the Fantasyland rides and start collecting FPs. That leaves 6.5 hrs for sleep.
One day a few summers ago we were did a day trip to DLR where we were there for rope drop and my kids convinced me to stay until 11:45PM - with no breaks except for meals - so about 16 straight park hours - and we parkhopped I think 3 times. I was so exhausted that evening and the next day I could barely move. In the above scenario one would have to wake up on Day #2 and do the whole thing again on a short night sleep.
Aside from the exhaustion factor, I still cannot see how anyone can manage to walk to each ride and wait in each queue and have that average 10 minutes per ride on a weekend day.
My experience is that would take at least 20 minutes minimum - which would require another 12 hours for 70 rides - or a third day at the parks - going commando all three days opening to close without breaks and limited sleep.
That is why I and many others would say DLR requires four days minimum to experience most all the rides and shows.