Many people don't care about anti-monopoly regulations, but they are not joke.
IBM and Intel for decades deal with anti-monopoly regulations and managed to avoid ATT/GM like issues (extremely serious troubles, in simple language).
People usually thinking, IBM distributed their soft as public domain and opened S/360 and allow clones, because they are good, but in reality, they used all means, to avoid 100% share of market, they intentionally made hidden moves to support semi-concurrents like AMD in 1980s, so anti-monopoly regulators didn't have enough foundations to issue things like made against ATT/GM.
In early 1980s, Commodore was nearly monopoly of home PC market (IBM PC at begin was expensive business machine, and Macintosh was even more expensive, when first appear). And I have seen from other business behavior, they behave exactly same, when appear close to hit some crossbar (of profits, or of gross budget, or of market share) which they don't want to hit, because they feel good enough under this crossbar.
If they have not so tight relations with hardware, they would show much more agile behavior to survive.