I can’t say I know the truth, but the sentiment is that Welch divested from R&D, focused on “financialization” I.e. investing in financial instruments over adding real value, made big short term gains, and doomed the future of the company.

GE used to be an R&D heavy company that paid it's employee's well. Welch, proved and popularized the trend of firing large business areas and hollowing out R&D to pump up the quarterly stock price. This was a sugar hit of profitability at the expense of the future.