I don’t think it’s just a UK thing, or that it’s much easier to start a hardware startup in the USA.
I think it’s more that the bar for getting a hardware startup off the ground is much higher than a software startup - everywhere in the world.
Personally I’ve been trying to self-fund and bootstrap a hardware startup (based in Australia but I’m reasonably well connected in Silicon Valley as I’m a YC alum). I’ve had plenty of early success and validation of all my market theses, but it’s super hard to get any investors interested. Plenty say “exciting” and want to chat. All lose interest when you start talking funding needs and path to market.
In a world in which investors and other startup industry contacts are accustomed to seeing a bootstrapped SaaS app showing signs of growth and revenue just a few months in, with a hardware startup it’s just impossible to avoid looking like a failure by comparison - due to all the costs, delays and complications involved with getting an MVP to market. And because successful hardware startups are so scarce relative to software ones, it’s hard even to get any good advice; there’s just barely anyone around with good, relevant experience to share (and I already know many of the people who have built companies in this vertical in past decades, none of whom are in SV).
I’ve come to the conclusion that the only way to make it work is to start by achieving success as a software startup, then transition into hardware to later - but even then you’d have to convince investors that it’s worth the risk.
In short, the whole tech industry has been spoiled by easy SaaS wins over the past decade, and that’s all that most investors are willing to even consider.
The exceptions are “start-big and-get-huge-fast” plays like Groq - but the founders of that company were already highly credentialed and connected when they started, and even then vanishingly few investors are willing/able to fund new companies like that. That’s not the kind of thing young, unproven founders can pull off, anywhere.