I do not share your experience. I used to commute weekly for 1,75 hours in one direction with ICE. I had rarely problems that lasted more than 5 minutes. There was no change of trains required which might help here.
Same here: I regularly take long-distance train rides throughout all Germany, both with ICE (the fast one) as well as RE (the regional one), and for me it works smoothly for the most part.
I worked for a company for 7 years and the only ICE (between our Munich and Würzburg office) I took that was not either: replaced with an IC, cancelled, or my reservation messed up... was the one to a company christmas party. So the table seat to be able to work on the ride happened exactly 0 times out of X where I tried. But I think they were at least on time and I wasn't stranded. Not that I should need to mention this...
