It's a bit ridiculous to imply Tokuyama gets better shinkansen service than Hamamatsu, because it has Nozomi service.

Looking at the schedule towards Tokyo for Monday, April 27th: Tokuyama has: 4 16 car Nozomi trains to Tokyo 19 8 car Kodoma/Sakura trains to Shin-Osaka 9 8 car Kodoma/Sakura to Okayama

Hamamatsu has: 31 16 car Kodoma to Tokyo 19 16 car Hikari to Tokyo

Keep in mind the fastest Kodoma seems to only take around 1 hr 40 mins to Tokyo, and the fastest Hikaru is only 1 hr 20 mins.

I'm sure it's nice getting a 1 seat ride to Tokyo from Tokuyama if you can get on one of the 4 Nozomis, and unfortunate you can't get a one seat ride past Shin-Osaka from Hanamatsu, but the service levels seem pretty proportionate to me.

Looking only at connections to Tokyo is a bit reductionist (difficult to believe, but yes, there are cities outside of Tokyo that people go to!). As a mere matter of geography, there are unavoidably fewer trains to Tokyo (it's on the opposite side of the island). Using that same methodology, it would be good to see how many trains from Hamamatsu have a direct connection to the biggest metropolis near Tokuyama: Fukuoka. That way we can measure which city is the best for getting to the opposite side.

The total number of trains with a direct connection from Hamamatsu to Fukuoka is, at least based on all the info I can find, zero.

Or even a much closer city that people in Hamamatsu would frequently go to: Hiroshima. Also zero direct connections without a transfer.

People in Tokuyama can go direct to Fukuoka and Tokyo. They can do a transfer at Osaka in the case of non-direct trains. They're very much better set up than Hamamatsu.