Default Why are web forms so slow on android/ios...?

Can somebody explain to me that why web forms are so much slower on android/ios devices than on windows computer web browsers...?

I am talking about pull-down menus, insert text fields,

For example look at the left side of the following page:

Now try to choose a value on all of the pull-down menus with 1. your windows computer, 2. your mobile device

At least for me it is at least twice faster to do this with the windows computer than with cell or tablet. With mobile device there is always some mysterious delay between touching the form element and pull-down menu appearing (or virtual keyboard appearing for input), same thing when you make a choice in pull-down menu there is a delay much longer than clicking a mouse in computer.

How about some flight booking with a cell or tablet (I hate it...):

Or filling search fields of a computer shop:

1. you wouldn't assume that using an interactive web page element would need a lot of resources. What is the reason why it is so much faster on a computer web browser than on a mobile browser...?

2. if I buy a device with a faster sunspider or browsermark result (e.g. snapdragon800 or apple A7) will these form element delays get significantly smaller...?