Question

similarities and differences between old and new temples

Answer 1

Old temples were built by ancient rulers with the aid of expert architects according to "Shilpa Shastra" (Traditional rules and norms for Construction of Temples) , not only to create an abode for the Idols of Gods for worship, but also had a provision of Secret Tunnels and connectivity with the Forts as a route for safe mode of escape of the Royals and their families from the Forts and enemies during the time of Wars. More often the Temples were also acted as a Safe Deposit value for the Wealth of Royals, who used the wealth for the welfare of their subjects.The old Rulers Gifted hundreds of acres of land other means of assets for maintenance and upkeep of the temple and the people who worked for the temple. While the most of the land belonging to the temples have been either grabbed by the Politicians or encroached by the squatters. the treasures hidden in the temple remain inaccessible to people due to the British invasions and no one from the clan who built the temples and the rulers are knowing the temple's secrets is available to solve the puzzle till date, unless some one accidentally come across the treasures as in the case of Padmanabha Temple in Trivandrum. 

The present day temples are reconstruction and/or expansion of encient temples and most of them are managed by the Goverment few are managed by Independant trusts like "Tirupathi Balaji Temple at Tirupathi at A.P. Shri Saibaba Temple at Shirdi, Shri Siddhi Vinayak Temple at Mumbai,etc. and the income from the trusts are used for meanly welfare measures....hope this helps!!!

Answer 2

Similarities between old and new temples
------------------------------------------------------------------
1)All temples are built according to vastu shilpi
2)Every temple will have a main god in the garba gudi itself 
3)every temples will have pooja according to the the traditional rules
------------------------------------------------------
differences between old and new temples
------------
old temples
------------------------
1)they were built by kings or emperors
2)they  were controlled by kings 
3)kings used to donate money to temples, used to store all their treasury in tunnels of temples
4)there were many carvings on temples which used to depict India's pride
5)temples were built in dense forests 
------------------------------------------------------------------
new temples
-------------------
1)government or math will control the temples
2)the profit earned by temples will go to the government
3)there are no much carvings in modern temples
4)there are rather built in towns and not in forests