How do you figure its a centralisation of power? There are 3 different lightning implementations to choose from, LND, Core and Eclair, you're free to use any one of them. If you want to use a custodial wallet by all means, if you don't you have the option to run your own node
Yes a lot of people will use custodial lightning because they don't want to deal with the hassle of channel management, but that's THEIR choice and the option to run your own channels is always there if you choose it