Web-IPFS gateways are not part of the IPFS infrastructure, nor are they essential.
If you also use a browser extension like "IPFS Companion", it can automatically redirect all IPFS-looking URLs to your local gateway.
I agree this doesn't help for casual users who have never heard of it, but it's at least better than "everyone has to use a public gateway all the time".
(But point taken, a lot of people aren't using general-purpose computers.)