Ok, I think this is too technical for me. So 46 MP is same as 36 MP for landscap?
No, 46 MP is higher resolution than 36 MP, for any application.
This is not ultimately true. According to the Nyquist theorem you get the whole information about a bandwidth limited signal if your samples are spaced close enough. Making more samples provides you with no new information. While the airy function is no sinc function, it is rather similar. So there is supposed to be a pixel spacing below which the quality gains become marginal. However i suspect this isn't the 50% contrast assumed in the calculations and if you consider the effects of the bayer pattern there should be a lot more pixels than we have today.