Because most of the time people get a chronological feed of everyone they follow, you get this waterfall where you have to hit a strike to grab some attention, and then that attention lasts for about 15 minutes or whatever. Your post on mining centralization/pools got some traction for example. Simply crossposting your feed, is also simply throwing your posts into the void; there currently are no significant platforms to pick it up and carry it for you on Nostr.