Motivated muslims but down fall is still there

Recently i received an email with inspirational snaps taken at different parts of world. Snaps demonstrate that Muslims are offering their prayers even in worst, unfavorable, depressed and miserable conditions. During Friday prayers in hot summer days, i have personally noticed that my fellow Muslims even offer prayer directly under sun without any shed.

Also you would find examples that several people used their whole life saving to perform Haj or Umra. Even suicide attacks are generated by same sense of dedication to Islam. Such motivation to religion always tends me to think that despite this involvement and dedication to Islam, why we Muslims are in continuous down fall since centuries.
It still leaves me blank without any answer. You may give several prevailed theories like lack of knowledge in Muslim world or bad habits prevailed in Muslim society but let me reject all such theories as i already undergone a long thinking process on these arguments and these proved failed in litmus tests.
So any one who read this post is invited to point out and explain the reason for long downfall of Muslims.
By the way if you want to see the snaps of Muslims offering Salat in various conditions. Download this .zip file 1.14 MB (as it is time consuming for me to display these in blog post).