Sublease for Passive income..?

[Leah Bonner]

Ok at a reiclub meeting I spoke with someone and he brought up the idea of Control without ownership while going to landlords offering them 5 year NO vacancy lease. Then he said to go ahead and RE rent it to other tenants for a profit. 

My question is , is that sublease(?) 
It just seems too easy...?? So after looking into it I found out that most landlords say in there lease they will not allow subleasing (OK thats fine, but if I'm offering them no vacancy, im sure they will accept my terms) 

So for example even if i dont offer the 5 year lease ( The man i spoke with just used that as his example because then he said during that time the owners would more than likely consider selling it as well.. So basically a lease option, but not.. since that term is illegal in texas) 

Ok back to the example I go to a person trying to rent there home for 700... I offer to lease no vacancy 5 years but ill pay 600 a month.. then I turn around and market it as 1,000 a month.
That house then turns into a $400 a month cash flow...

Is it truly that simple???  what am i missing here, it can't be that easy.
(Or maybe it can since there are SO many ways to control real estate)
ANY professional advice would be appreciated :)