Well, I get about the same results with peppers as you do. I get 3-5 peppers and then they are done. Tomatoes take more heat than peppers do and where I live there are too many diseases and few peppers have the resistence to live very long. Peppers can be grown year long in frost free areas. Although bell peppers are a warm season crop, they don't really like the hottest parts of summer and do better with milder temperatures. Pepper seeds germinate best at 70 degrees but the plants can handle down to the 55 at night. Day temperatures above 80 will start to cause problems. Peppers like warm and dry. They do not like a lot of rain falling on the plants or high humidity. Those conditions bring on bacterial and fungal diseases. Some cold tolerant ones like gypsy will do better in cooler areas. For me the best peppers are Jupiter, California wonder, yolo wonder, Chinese Giant, chocolate bell, yellow bell and Keystone. The University has a pepper called Kaala which is the only one that has enough disease resistence to last more than a year. It is a mini pepper. Hot peppers like the heat, but other sweet peppers like bull horn, banana, and cubanelles are more productive and can handle the heat a lot better.
Peppers like a lot of sun but not hot sun. In midsummer when the heat is on, it is best to have the peppers shaded in midday. Planting them in pots help since they can be moved to morning sun location in mid summer. I plant peppers in 5-18 gallon pots. Most of my peppers do not live long and they do get to be 18-24 inches. Some peppers are taller, but that seems to be a varietal thing. Peppers do need a bigger pot to get to a larger size. The same pepper grown in a two gallon pot is 1/3 the size of a pepper in an 18 gallon pot. Bigger root systems = bigger plants. The capsicum anuums rarely live long; and most don't live a year. the c.bacatum, c. frutescens, and c. chinense are mostly hot peppers from the tropics and they are less susceptible to disease and live a lot longer.
The solanaceous fruits like even watering and a slightly acidic soil. I usually feed my peppers regularly once the flowers set every month. I give everything in pots citrus food. 6-4-6 plus micros. about a tablespoon per plant per month.
Happy gardening in Hawaii. Gardens are where people grow.