This is the trap of many founders -- they confuse the product for the business (many tech VCs do too, unfortunately). Everything you mention is about engineering and the product. The product is just one aspect of the business. There are so many others things that are vital.
The best protection against being "knocked off" is to have a strong BUSINESS.
You need solid distribution -- if you lock in the best distribution channels, and your competitors don't have as many points of distribution, then you have a huge strategic business advantage.
Discovery is at least equally as important as distribution -- If someone knocks you off, but nobody knows they exist, and you and your product are easy to discover, then who cares, you win. Even if they're cheaper, nobody has heard of them (this is where marketing matters: getting your signal above the noise). Good marketing gets your brand story above the noise of every other communication.
Support -- Someone could knock off your product, but have terrible customer support, miss delivery deadlines, outsourcetheir support to some other "support startup" which means they own your customer service experience (do not ever do that, then you're nothing but a product, not a business).
Engineers often use Androids, and mock Apple users as dumb and just buying a name, and other such accusations. The fact is, Apple consistently is ranked Number 1 in customer service by every industry trade organization that measures such things, not just for a tech company, but any company of any kind. Engineers typically undervalue tech support because being an engineer, they rarely need tech support for a consumer tech product, they're likely more educated on the technology than any tech support personnel would be, so they think customer tech support is useless, or holds little value. This is dead wrong. For a consumer product, you should imagine your grandmother as the customer. Now how good does your support have to be to competently give your grandmother support in using it? If you have an easy product, maybe not so much. On the other hand, if you have a complex product ("complex" by your grandmother's standards, not your standards), then your tech support better be well trained and up to the challenge.
Product Design matters -- good design and good build quality = higher prices and higher margins, but possibly lower unit volume, as price sensitive customers won't pay. Conversely you can do cheaper price and lower build quality, but larger buying audience -- this is the route most naive hardware startups take. Notice all Android phone manufactures have razor thin margins? This is the death-spiral of competing on price.
Apple's iPhone makes up about 35% of the smartphone market but captures 92% of all industry profits. Don't sell on price, sell on quality, and command a higher margin (and by quality, I mean the entire customer experience, end-to-end).
Don't just be a product, stand for something. Find your brand's attitude, what you believe in as a founder. To use marketing speak: What are your core brand values? Make people fall in love with your brand. Brand is not just your company's logo mark. "BRAND" is a cumulation of how all the things listed above make a customer feel about your company. That feeling, that mass opinion, that is your brand -- not your mark -- Your logo is just the symbol used to associate your brand with your product.
Do all of these things well and if your competitor just knocks off your product, sells it for 10 bucks less, and thinks they're going to steal business, they will fail, and fail miserably. Nope, they will only capture the most price sensitive customers that happen to stumble across their offer, and they are the customers of least value. They're not even going to come back for their next product anyway, they're just going to look at who has the cheapest price tag, so you can forget repeat business. Don't just build a product, build a whole company. Don't compete on price, compete on quality, and you'll never have to worry about getting reverse engineered. Any good product will have knock-offs, but it is the great company with a great product and a great brand that will succeed.