"Can anyone develop a big beautiful voice?"

Yes. Anyone with a speaking voice who is not tone deaf can develop a beautiful singing voice. The is a science of Beautiful singing call Bel Canto that holds the key. We all have similar body and great singers are doing similar physical things to produce a beautiful vocal tone. On Bel Canto technique, there are 3 core elements that will help you achieve great results: 
1.  Use proper breath support.  There are many schools of thought on what proper breath support entails.  The most effective method is one which follows the following progression:  Take a spontaneous open breath, passing through "Ah."  The lower abs should come out upon inhalation. As you sing a line of a song, pull your abs in gradually and then release the abs at the end of the sung line. Your neck, shoulders, and jaw should be relaxed and your shoulders should never come up.  Some vocal schools teach students to expand their ribs horizontally outward upon inhalation.  This is incorrect!  It will largely limit your vocal range and result in a  wobbly vibrato.  
2.  Sing pure and stationary vowels.  Pure vowels are vowels where the consonant following the vowel is not sung or blended into the vowel.  In contrast, dirty vowels, which occur when the consonant following the vowel is sung or blended into the vowel, make your voice smaller. Stationary vowels refer to the sound of each vowel having a form.  
3.  Utilize proper placement and vocal resonances.  Using frontal placement, focusing sound on the hard pallet, and engaging vocal resonances will amplify your voice.  These elements are brought together in three voice building tapes that my students do in their lessons and at home.  These tapes are incredibly effective.  They are not posted online due to the fact that they must be executed properly with a voice teacher.