en.wikipedia.org
'The F/A-XX is being pursued as F/A-18 Super Hornets will reach the end of their 9,000 hours of service life by the early 2030s. Aside from the option of buying more F-35Cs, the F/A-XX is seeking to create a new aircraft to replace the Super Hornet's capability and mission set. Just as the F-35C will replace aging hornets and complement Super Hornets, the F/A-XX will replace aging Super Hornets in the 2030s and complement the F-35C'
C/D models of F18 had like 8000 hours. E/F have 10,000-12,000 depending upon the stress faced and conditions of the airframes. So F18 is not going out so soon from USN service actually. 2040 is the minimum.
USN is receiving new-build Block-3 SH as we speak. The current order will continue deliveries to USN till 2024.
The F/A-18C/Ds served for nearly 40 years before retirement. The older Block-2 SHs will retire but the Block-3s will serve into 2050s minimum. By that time, there could be upgrade packages that convert them into unmanned aircraft.
Australia is retiring its Block-2 SHs early due to the RAAF fighter fleet not being built around a hi-lo force fix, so a single type (F35) suffices. US does not operate in this way.
Come to think of it, given how relatively new the RAAF SH airframes are and the fact they will be retired in the next few years, they could become an option to increase IN's numbers from the initial 26 in the future at a fraction of the cost of new-build airframes (if we buy SH, that is). They can be refurbished, zero-life the airframe and upgraded to Block-3 standard avionics. This could be an option if SH production line closes after 2024.
Yep, this is my argument too.
But the requirement in that case cannot be met by TEDBF.
Only carrier that has a reasonable excuse to operate TEDBF is the Vikramaditya due to obsolescence of MiG-29K platform, and it being seemingly impossible to operate Rafale from it due to the size of the aircraft elevators, and the inability to make modifications due to their location in the middle of the flight deck instead of to the side as on Vikrant (making SH a single-vendor choice). IN appears to have 'relaxed' looking for a new jet for Vikky as is evident from the requirement dropping to 26 - just sufficient for Vikrant.
However IN itself has spoken about retiring Vikky by 2040 - a service life of less than 30 years is an indication of a lack of confidence in the ship's ability to perform beyond that. As doing so would lead to grief of a similar nature as being experienced by the Russians with their Kuznetsov, which shares a largely similar propulsion complex as Vikky.
So it could actually be relegated to role of a training-only carrier much earlier than that - flying only two seat NLCAs or F/A-18Fs to keep the pilot training & flight hours up even while Vikrant is in dock.
Such a carrier will not require its own air wing of spanking new jets, much less justifying the development of a whole new platform (TEDBF) which in fact could enter service only a few years before Vikky itself retires.