Good answer from Slotser.
I could try make it even clearer to understand maybe.
Think about scratchcards. You have 1 million scratch cards which you normally have 1 or 3 top prizes of a million or more. Then you all other prizes are spread across all the tickets.
If a batch is 1 million and you go to different stores it does not matter and does not give you bigger chance of winning where you buy or if you buy lets say 10 tickets from one store or 1 ticket from 10 different stores.
The same is when you play a slot like Dead Or Alive. Every time you take 1 spin it is basically taken out of maybe a 1 billion spins batch (please note this is just a random example and not correct figures)
So if you spin 1000 spins at one casino or 1 spin at 1000 casinos makes no difference as each spin is random. Each spin you make at a casino takes that spin direct from the software providers database.
This is why in reality you could get 5 scatters 10 spins in a row. But yes does not just happen because it is all like a big batch of numbers lottery.
Hmm I do hope above made any sense hehe. I should really read it proper through and edit but hope it is clear and understandable at least
Also of course the longer you play one slot and more spins then of course you would build towards the RTP so some might say that the longer session one a slot would give you back sooner or later. But always dangerous to chase a big win.