I don't have any experience with Amazon, but at least with Oracle we found it very difficult to actually get them to use some of those "financial resources" for even basic things. I would imagine Amazon is willing to do whatever it takes to make the best possible product/ecosystem. I don't have the same confidence that Oracle will.
You know, nine women can't make a baby in one month. That surplus they have is very hard to spend effectively. And amazon is growing much faster than Oracle, that's why they can spend their surplus on that growth.
And Oracle does dwarf Amazon, significantly, in terms of financial resources. That's not a subjective opinion, it's an easy direct comparison.
Amazon has $7.6 billion in cash, a pile that is contracting rather than expanding, and they have to fund the continued expansion of their retail business, investing billions into new fulfillment and automation. Meanwhile it's highly unlikely Amazon is earning much profit out of AWS itself. Amazon produces some cash flow, but they do not produce net income, and do not compile much cash to their balance sheet from operations.
Oracle has $39 billion in cash, net income of $11 billion, and even more cash flow. Out of $37 billion in revenue, Oracle generates $14.6b in operating income; Amazon generates approximately zero operating income.
To put it all in perspective, Oracle generates more net income per quarter than Amazon has in its entire history. Oracle generates more cash per year to its balance sheet than Amazon has in the last ten years.