Yes, and why?
Like you said, you already know 4 years in advance who will probably be fighting for the leadership, as we do. So you can keep tabs on them. You don't have to have an actual drag em out primary fight for a full year.
As far as the general, it doesn't really start next year in the US. Trump has been campaigning since his first day in office. And your media treats it that way too. People don't talk about who is best to lead the Democrats, its who would be the best performer in the next general. Which could be argued is the same thing, but not exactly. Because a candidate, or leader, can be decided years ahead of the general here. And here, leadership primaries, which only last a few weeks, are decided by party members, much like party delegates decide down there. One difference is that it is shorter because it is held at one place in the country, which changes. Delegates, or members, come to them, not the other way around. No country wide tour as part of a primary. Which takes time and money, but I can understand if that is important, to physically visit every State. Would be nice, but all of this adds up to a perpetual war. It doesn't bode well for bi-partisanship or compromise, even in the best of times.
And then to top it off, you do this again two years later federally, albeit with less at stake. There is no reprieve. Not to mention the massive cost it takes to run such long campaigns.
But we live in a Parliamentary democracy, such as the UK. So that affects a lot of things too. We need to decide on our candidates at least a good year or two before an actual election just to have a "leader of the opposition" to represent the individual parties during the rest of the time. Our "speaker" is largely symbolic, and meant to basically keep order in the House.