I am not debating on the fab plant or that we currently also use the Ariane. We are quite some time away from putting heavier satellites, read 4+tonnes. up. Till date the tonnage is 2.5 tones. These are routinely launched now under the GSLV MkII vehicle. Most GSAT launches are now using this vehicle. The Ariane launches were planned much before we had the MkII successfully tested. The heaviest MkII is expected to be the Chandrayan 2 at 3.1 tonnes.
I was pointing out that we do have HTS satellited in the pipeline. As in most ISRO programs, they concentrate mostly on things which is not available off the shelf. Then replace the foreign components with India made replacements.
Also, please understand ISRO does not compete with the top agencies for launching heavy satellites. Their commercial success is in launching small satellites in a quick affordable manner. Its only recently that we have stated onto the mid size satellite space with the CE7.5 engine found on the third stage of the GSLV MkII.