I think even Laidlaw's original ideas spilled out on Twitter would have changed dramatically had Half-Life: Episode 3 production moved forward. As is the case for more or less every game, but especially Valve's, which are subjective to important story beats being influenced by game design and production restraints. The classic example being the "slow teleport" in Half-Life 2, which ultimately became a pretty strong cornerstone of the Combine lore, battle against the resistance, and necessity to research alternate technologies. In reality the "slow teleport" was the result of production issues; Valve were running out of time and needed to get Gordon and Alyx from the Combine base back to City 17. With no playable levels to fill the gaps and production windows closing they inserted the slow teleport idea and the rest is history.
I still feel this ending is awful. Time travel retcons are fundamentally bad writing as far as I'm concerned, particularly in their laziness, and I'm really disappointed this is the direction they took. People will argue that it fits the series and G-Man and lore but it doesn't really. It's just overruling Episode 2's ending with convenient space magic for no reason, while inserting new complexities into the lore that were never there. For all its ambiguity as to the G-Man, the multiple dimensions, etc, there wasn't really any mystique as to the passage of time and causality. Time still operated with linearity and there was direct, irreversible causality from actions. Not so much now.
Is what it is though. I guess we'll have to wait and see where the series future goes. I do think now, more than ever, there is a legit probability of Half-Life continuing in VR form. Valve did essentially make four games back-to-back using Source 1 and the Half-Life formula. VR Half-LIfe is a single entry, so there's plenty of room to grow before burnout, and I can imagine having a fully stabilised build of Source 2 and such overwhelmingly positive reception is givng the teams a big motivational boost. I do wonder if we'll see Portal 3 first though.