Without a monopoly a corporation will find it very difficult to justify research that can be used by other businesses.
The transistor was a disaster for the Bell System. It was not particularly useful in the telephony system of the day, which used high voltages in tube transmission equipment and high, intermittent currents in electromagnetic switching equipment. On the other hand, the 1956 Consent Decree forced the Bell System out of other businesses (audio, computer, consumer electronics, etc.) and out of other countries (Canada, Caribbean). So the Bell System could not use it's new transistor to expand in the businesses where it fit, and having a fundamental patent on it exposed the Bell System to great anti-trust scrutiny and greater regulatory duress, such as the FCC Computer Inquiries.