Wall Street must get back to its roots, says one veteran insider.

Ronald Kruszewski has been the longest-serving CEO among the major investment banks, taking the helm at St. Louis headquartered Stifel Financial Group (SF - Get Report) in 1997. As Stifel's CEO, he has navigated the highs of a tech stock boom (1999), the lows of a tech stock bust (2000) and the super lows of the Great Recession (2009).

During this span, Kruszewski has built a powerhouse in investment banking and equity research, primarily through aggressive acquisitions. Kruszewski has taken Stifel from about $100 million in revenues to $3 billion. The company's market cap has gone from $40 million to more than $4 billion. 

Hence, there are very few (if any) better names out there to discuss what the future of Wall Street looks like 20 years from today. Key in a future dominated by power players with their eyes on the financial prize: staying true to the reason why Wall Street exists in the first place.

"What Wall Street has to do is get back to investor trust and confidence, we have done a lot as an industry to lose that," Kruszewski tells TheStreet. "Wall Street's challenge is to remember that we are the fulcrum between savers and people who need capital -- we will rebuild that."