Why is the stack so small?

Question

C++ / C#

Large programs consume a lot of RAM. And the stack is only 1 mb. It turns out that gigabytes of RAM are occupied by types
object
string
class
interface
delegate
And another sub-question:
There is a class. It contains an int variable. Does it occupy memory on the stack or on the heap?

Answer 1

You save only a link to the stack, and gigabytes are allocated somewhere there. Well, the stack may not be 1 MB, but is set in the PE header of the executable file during compilation, as long as the compiler considers it necessary.