Do you think the PS5 will dominate this generation or will it semi-flop like the PS3?

At this point the only people able to buy them are scalpers, and normal users have been shut out of the market.  So it won't be able to take off until Sony and retailers figure out how to stop the scalpers and actually get the consoles into the hands of the public.

PS3 was a success it outsold WII and Xbox 360 in the end.

How was the PS3 a flop???

If you combine the economic downturn with the speed at which new consoles are released, it will not take off before the next generation console is released in a few years. 

1) PlayStation 3 was not a flop. It sold 80+ million units. It did pretty well. Besides, if you meant that they lost money then while that might be true, but most consoles will lose the company some money to some degree but the reason why PS3 had lost Sony a bit more is because their plan was to put as many Blu-Ray devices in house holds as they can during the Blu-Ray and HD-DVD war. Reason why is because Sony owns Blu-Ray and you know which one of those 2 won.....

2) PS5 might not be doing too well right now but that’s on the scalpers who intentionally buy up as many of the consoles as they can get their hands on through bots because the bots is faster and all that caused a shortage. So whether its going to be a flop is too soon to tell.

3) I doubt it will flop in the long run because chances are, given the amount of demands there is, I think it will sell at least 50 million units by the time the PS6 rolls around the end of this decade.

It will dominate because Xbox is still not that popular outside the U.S and the UK.

Neither. I don't think it'll dominate or flop. 
They're not selling (or making) enough of them for it to dominate, and the controller issues are holding it back somewhat. But it still is a good console with good games so it won't flop.
I don't want either of the big 2 consoles to dominate, I want them to be close so they keep fighting between each other to improve.

uhh ps3 was not a flop

I think that sony and nintendo will both dominate the console market, leaving microsft behind