I think people generally tend to conflate different types of banks. Using broad terms there are generally 3 “types” of banks of various sizes and geographic footprints.
Retail Bank- these institutions deal with consumers and small businesses and typically engage in deposit taking, traditional lending, mortgage origination and credit card services supported by a physical branch network.
Commercial/Corporate Bank- customers tend to be mid size/large or global corporations or financial institutions. Products include transaction management, revolving and drawn credit products, cash management, etc.
Investment Banks- a broad term that often includes a broker dealer (securities business), mergers and acquisitions, advisory, etc whose customers tend to be corporations, financial institutions and sophisticated investors.
None of these descriptions are all encompassing and many banks have several of these “types” of banks under their global umbrella and are licensed uniquely based on jurisdiction.
With that in mind please consider that approximately 50% of people who work for banks (retail, commercial or investment) are not bankers. Support teams (previously called back office) include areas like finance, risk, legal, compliance, operations, audit, communications and HR. These professionals ensure regulators are satisfied, staff hired, risk parameters maintained and everything else that needs to take place to ensure front office teams can support customers and produce revenue.
Most people when using the term investment bankers have visions of the aforementioned “front office” roles. Again I will use broad terms…
Sales and traders are the teams of people that facilitate the buying and selling of financial products such as bonds, equities, FX, interest rate hedges or commodities.
Capital Markets teams are responsible for supporting customers who are seeking to raise capital.
Lending Teams maintain the high level relationship with customers and are the point people for coordinating direct lending to their customers.
I bankers (traditional role) typically have both sector and product expertise and often have senior C Suite relationships that allow them to offer strategic advice and solutions. Think M&A, corporate advisory, etc.
The skills sought vary by area and in my experience there is no “secret sauce”. Both written and verbal communications skills are highly valued along with the ability to be persuasive. Proven track record of both academic success and resilience are also valued.
I often smile when reading on CC about the lack of commercial marketability of humanities majors and then attend an event where everyone at the table are former history, English and classics majors who wind up talking about Ayn Rand or the Opium Wars to contextualize a current world view. At least in my experience the more senior the participants the less “technical” the conversation with the exception of course when in deal mode, and then it’s all about the details.
Intellectual curiosity and the desire and capacity to assimilate diverse experiences and subjects into a nuanced world view seems to be the common thread of what is sought, recruited and ultimately seems to succeed.
Hope this starts to answer your question and sorry if I rambled😀