..... Yeah no you can't.
We'll ignore the fact that no scrolling combat text, including this FlyText accurately shows all damage your character does. It will double up and also sometimes fail to display damage values entirely.
But hey, do I really need to go on? You are telling me you can accurately gauge dps from looking at scrolling combat text.
Well.
I'll do you one better. I can make cats float by dancing. The only valid argument for dps meters if performance gauging, which can only be done real time.
....... Also I just noticed you seem to think the damage values on the abilities tool tips somehow reflect your characters damage per second?
Those two bits of information have absolutely nothing to do with each other. One is a game guesstimate of the average damage the ability does, whereas your dps is based upon your real-time damage per second in varying raid encounters, this encompasses your knowledge of your class as well as LAG, and hundreds of other factors that go right down to the armor values of the target you are hitting.
And just elaborating slightly on that last point, this is why DPS meters are so crucial to gauging DPS performance. Your average dps on a target dummy was, is and always will be irrelevant. It in no way indicates your ability to perform within a moving living encounter that requires many outputs for your attention.