That's completely not true. The intent of Enterprise was always to lead into the Trek continuity we knew, which is why it did so many episodes setting up elements from TOS and later. The Temporal Cold War was forced on Berman and Braga by the network, over their objections. They wanted to do a straight prequel, but the network was uncomfortable with that and wanted to include elements that went forward from TNG/DS9/VGR. So Berman & Braga tossed in some vague time-war stuff that they didn't really have any investment in or any coherent plan for, then spent as little time focusing on it as they could get away with and eventually ditched the whole thing. Frankly I wonder if they deliberately did a half-hearted job with the time-war stuff so that the network would eventually decide it didn't work and allow them to stop doing it. Because what they wanted, what they intended, was to set up the existing continuity. Any perceived difference in execution is a matter of differences in storytelling style and individual creators' interpretation, just like TOS, the movies, TNG, and the rest all have their own differences in style. Every single followup to TOS has been dismissed by some fans as an alternate reality. Three and a half decades ago, there were people who insisted that TMP and TWOK had to be a separate reality from TOS. After all, they argued, the technology was much more advanced-looking, the Klingons had a totally different appearance, Khan knew Chekov somehow, Starfleet was more militaristic in TWOK, etc. How could it possibly be the same reality with all those differences? But the truth was that the differences were a matter of style and interpretation, as is inevitable in any work of art that comes from multiple hands. They were still meant to be representations of the same continuous whole.