Why do you think that? You could absolutely "build a website covering FE and BE without the hydration performance hit" using standard practices of the time. Yo

Why do you think that? You could absolutely "build a website covering FE and BE without the hydration performance hit" using standard practices of the time. You'd render templates in Jade/Handlebars/EJS, break them down into page components, apply progressive enhancement via JS. Eventually we got DOM diffing libraries so you could render templates on the client and move to declarative logic. DX was arguably better than today as you could easily understand and inspect your entire stack, though tools weren't as flashy. In the 2010-2015 era it was not uncommon to build entire interactive websites from scratch in under a day, as you wasted almost no time fighting your tools.