I can’t say it’s a persuasive argument for selecting one.
I don’t think you’ll find that the competition differs much. Realistically, very few people can claim to follow these instructions religiously – with forks, shocks, or seatposts. Thankfully, manufacturers know this, and don’t tend to make a fuss when people claim under warranty within two years.
Once a product like this is over two years old though, retailers will quite understandably look to wash their hands if the end user has done no maintenance (not suggesting this is the OP’s case, he may have been looking after it exactly as recommended).
I’m not sure whether it’s more unrealistic to expect an end-user to service their seatpost every 100 hours, or for said end-user to expect a product like this to continue to work flawlessly in UK riding conditions if it’s not maintained at all. I’m sure there’s a middle ground in there somewhere…