Ohio-class SSGN can carry 154 Tomahawk cruise missiles with 22 tubes (each tube carrys 7), which gives USN overwhelming fire power.
Why 09V's VLS fire power is so weak? Is that reasonable? I still think 8 tubes are too fewer.
Why are you comparing apples with oranges?
The Ohio SSGNs were originally SSBNs before the first 4x boats were converted into SSGNs the 2000s. Each of the those 4x Ohio SSBNs had their 24x SL-ICBM tubes swapped with 22x multipack VLS tubes with 7x VLS cells each for the Tomahawks for a total of 154x Tomahawks.
It must be noted that the Ohio SSGNs won't be serving beyond the end of this decade as they are more than 40 years old by this point. That's why the Block 5 Virginia SSNs were conceived in the first place.
Comparing with the Ohio SSGNs, each of the Block 5 Virginia SSNs can only carry a total of 40x Tomahawks across 6x VPTs, or a total of 12x Tomahawks in 2x VPTs + 12x CPS in 4x VPTs. Moreover, in order to fit 4x additional VPTs, the Block 5 Virginias are literal swimming baguettes. This introduces significant impacts on their speed and maneuverability (as those boats are still using the same propulsion systems as the previous blocks), both of which are crucial parameters for any SSN.
Hence, if there's a real need for Ohio SSGN-esque SSGNs like the PLAN - Converting the 094/A/B SSBNs into SSGNs once 096 SSBNs are available in sufficient numbers for China's sea-based nuclear deterrence stance, or just develop an SSGN variant of the 096 SSBN would do.
Furthermore, don't forget the fact where the Ohio SSGNs and Block 5 Virginia SSNs are only equipped with Tomahawk cruise missiles which are both only subsonic-capable and non-stealthy. On the other hand, the 093B and 095 SSNs are capable of fielding a variety of both hypersonic missiles (YJ-17, YJ-19, YJ-20) AND subsonic stealthy missiles (YJ-18C).
And speaking of the aforementioned CPS (which is the naval variant of the LRHW) - Those are very much the only hypersonic missiles that can be fielded by American SSNs, and those CPS can only strike fixed targets for the foreseeable time to come. On the other hand, all the YJ-17, YJ-19, YJ-20 and YJ-18C are able to target moving warships.
So there's that. Merely comparing launcher numbers is far from being useful in providing a holistic and comprehensive picture.