If a start-up wishes to make big bucks in biohacking it has to deliver a product that is in wide demand by the general public. The reagents on sale mentioned (Taq, antibiotic resistance genes and DNA ladders) are to biotech what solder and resistors are to electronics, i.e. very low value products of no use to the general public. The real hurdle for true "biohacking" is the cost of laboratory facilities and equipment…
This is what my startup is working on! Check out https://www.transcriptic.com . It's still early days and we'd love feedback.
I make a mutation of enzyme X, then test it. Ok, the procedure works, now let's scale it to 48 mutants. Uh oh, the procedure stopped working at #28. Why? Because the batch number for our competent cells from NEB changed and it no longer accepts our plasmid. (real situation) Etc.