How hard is it to develop and maintain for Linux compared to Windows?

As someone who uses windows and linux, it is far far more convenient to download and double click an exe file than to install a program on linux, yes I know u can just open the terminal and do the sudo apt install commands, but imagine the process for an app that u have no idea of yet and are googling and looking to install.

Similarly I was looking to install a software and faced this inconvenience, I got curious, if it is this troublesome and inconvenient for an average user how troublesome or inconvenient must it be for the developers to develop for and maintain for linux. Also considering the size of the linux market why do developers even go the extra mile to support linux (which I am very grateful for), which I assume are fairly demanding customers who are hard to please.