Cost is the main reason. The Yak is much cheaper and can do a lot as well. It can also be 48 Mig-35K but the drives only unnecessary costs in the amount and by the pilots fly less.
When the primary fighter on the K was the Su-33 which does not come in a two seater version then it made sense to have two seat trainer versions of the Su-25 on board because simulations are not an acceptable substitute for learning to land on a carrier at sea... you need to do it for real in a real aircraft.
When it comes to cost a blank rifle bullet is cheaper than a standard rifle round so what you are saying is that Russian infantry should have half the ammo they carry in combat should be blanks... it is cheaper and when they need to kill someone they can load live ammo.
Like I was saying with the Su-33 as the primary fighter on the carrier you could argue that a light fighter bomber version of a Yak-130 could be an alternative to do the job of light short range attack and also as primary trainer, but with the MiG-35 it simply does not make sense to replace effective combat aircraft with shorter range slower much less capable aircraft just for training and light dumb strike roles.
Much of the time a modern carrier will be facing the air power of land based forces, which means potentially very capable air arms. The MiG-35s will be pressed even just in numbers most of the time, let alone the Yak130 which would be way out of its depth against pretty much any modern fighter or previous generation fighter.
By all means have several units at both land based carrier simulators, but at sea the flight training can be on MiGs to keep up skills.
The small amount of aviation fuel you save is just not worth the loss in capability the carrier has with a full compliment of real combat aircraft.
Agree. Russian NAVY should buy a squadron or two of Yak-130 trainers for their Yeysk training center, where NAVY could school their own pilots, a squadron of MiG-29KUB for constant carrier pilots schooling and training and a squadron of Su-30SM for ground based naval pilots trainings. With having both fighters there, pilots could as well train their air combat skills.
Have they even developed a carrier capable Yak-130 yet?
Personally I would wait... they already have Su-25 based trainers... there is no point getting YAK to make a dozen Yak-130Ks only to find the next gen carriers will have EM Cats and need modifications to the Yak-130Ks... building just 12 and then redesigning them for EM cats and they wont be that cheap. especially when the Su-25s are already doing the job and two seat MiGs are able to do the job too.
Even an 20 million dollars per Yak-130 modified for carrier use and produced in relatively small numbers... that is a lot of fuel... it would be cheaper to continue using Frogfoot aircraft.