Walt Disney Productions (WDP) was a small company until the mid-1950s. At the beginning of that decade, gross annual income was about $6M. After the opening of Disneyland, it jumped to $27M. By the end of the decade, it was up to $70M. That still made WDP a relatively small company with great brand name recognition. As examples, WDP made $3.4M in the 1958-59 fiscal year but lost $1.3M the year after. In Walt's last full fiscal year (1965-66), company profits were up to $12M.
In order to fund DL, the Disney brothers had to sell off much of DL's ownership. For $500K cash and a guaranteed loan for another $4.5M, they sold 34% interest in DL to ABC. Another 13.8% went to Western Printing and Lithographing for $200K. Walt himself purchased 17.5% ownership for $250K. Bank of America funded most of DL with a $11M loan. At the time, Bank of America was nervous about that loan amount, believing the company would not survive if DL failed. Walt reportedly was about $100K in debt until DL's finances fell into place, at which point his personal worth quickly recovered. DL was a huge financial risk and it took several years to pay off the original loans. Eventually, WDP bought back 100% ownership of DL (using more loans to do it), including purchasing Walt's share and buyouts of all the concessionaires in DL. Walt resented having to pay ABC $7.5M to buy back their interest in DL, Walt feeling they hadn't done anything to deserve it. Regardless of what Walt felt, they couldn't have pulled off the deal without ABC's backing.
The company had a string of TV and film successes from the mid-1950s to the mid-1960s, topping it off with Mary Poppins which was Walt's biggest commercial success. It was over this 10-year period that Walt amassed most of his wealth. Still, company revenue and assets were dominated by DL, and by 1965 they had invested about $48M in it.
They spent something north of $5M to purchase the land in Florida. (27,000 acres averaging about $200/acre.) They had to scrounge around a bit for that money but it wasn't too difficult. Still, the original cost estimate for WDW was $100M and WDP didn't have that kind of collateral. Rather than take out loans, Roy Disney did something creative and issued convertible (to company stock) bonds to pay for WDW. Due to the success of DL, these sold very well and WDW opened debt-free.
The last 10 years or so of Walt's life were his best financially. Yet even then, studio heads considered WDP to be a minor studio. There are stories that Walt had a pretty big chip on his shoulder, feeling that the big studio heads treated he and his brother like country bumpkins.
Walt's greatest asset was his public persona. To the public, he was the company. Nearly 50 years after his death, Walt Disney still is the face of The Walt Disney Company.