By the way - all these folk suggesting extra features (like self-ignition) -- how much are you prepared to pay for these features? And how many would you expect to sell each year?
One reason for the 'good enough' design being stable (for about a hundred years) is the small size of the target market, and the fragmented distribution system.
Its not like an iPhone, selling plural millions each month, (and still not being considered enough of a success!)
My guess is that selling a thousand products in a year would be a remarkable success.
And that most buyers don't see any reason to pay more than at present. (None of mine cost more than £20, delivered.)
Which is very limiting on manufacturing investment (tooling, etc) for a "better" version. Let alone additionally replicating the features of a £20 blowlamp, enhanced for safety due to the gas store being adjacent to the fire...
Something that could be added cheaply and easily, (as well as the plug), is a small lever to open the thing. Old tar, etc can make it hard to open - something along the lines of what is found on a boot polish tin would be nice...