How can $60 be considered a lot of revenue compared to like $15,000 for solving a block?
Perhaps I was unclear.
a store increasing the price of its' widgets by 1%, assuming sales stay the same, will likely increase profits by far more than 1%.
Mining revenue is comprised of the block reward (25 BTC + fees).
Mining profit is what is left over after all costs are paid for.
Costs are significant. Hardware amortised, electricity costs of powering and cooling the hardware, to name two examples.
Another analogy to try to illustrate the point (simplified dramatically, of course).
Imagine that it costs MegaPhoneCorp $500 to produce, distribute, etc their latest handset.
They could sell it at $550. Then they make $50 profit per handset.
At $560 they'd make $60 profit per handset.
A small difference in sale price (~2%) leads to a large difference in profit (20%).
In the mining case, I can't tell you how large the 'multiplier' would be, but it's certainly true that looking at the straight percentage of block reward made up by fees is nonsense.