No you just don’t understand the metaphor.

If electric cars cannot be sold, If for example they were actually illegal, then how do you sell electric cars? If

If you have to use the Safari engine for everything and the Safari engine doesn’t support a particular feature, then there is no way to use that feature on iOS. You can’t develop a workaround because the work around would require you to have access to arbitrary system commands, and that’s not how web development works.

For example, there is absolutely no way to implement notifications on iOS without iOS support for web notifications, without that API there is no way to interface with the operating system. There is no way you can build workaround code for that.