Matchroom Sports did 650 events in 2019, so pool was less than 1% of its business by volume, and probably even less than that in revenue generation. One can reasonably wonder whether Barry Hearn thinks about pool more than occasionally.
You say "Barry Hearn has the money, the time, and the ability to deliver pool". It's a false statement. What Barry Hearn has the ability to do is market and sell a good sporting product and to direct his company's investment dollars into things that are or are becoming more financially lucrative than others. He also has the wisdom to deemphasize, or even walk away from, underperforming investments.
Pool will have to justify greater investment from Matchroom Sports or it will remain near the bottom of the pecking order at Matchroom. For over a year now, Emily Frazer has made it clear that starting to tidy up the image of the seedy, unrefined American pool pro is fundamental to her plans to grow pool, and yet at the Mosconi Cup last month, Team USA did not take the trouble to present itself with a sufficient level of professionalism. Many on this very forum expressed embarrassment and shock over how a couple of players on Team USA chose to present themselves. Only the delusional believe that pool is a sufficiently developed product to warrant many attentions from Barry Hearn and other powerbrokers who produce sporting events, but looking forward, perhaps pool can be such a product.
Matchroom's acquisition of the US Open 9-ball and the WPA World 9-ball are positive developments and if Matchroom has a good experience with them, perhaps they will consider increasing their investment in pool as a sport. Unfortunately, the quality of the professional pool product does not lie in Matchroom's hands alone, and the American pros, long a thorn in the side of pool event producers, will need to get out of the way.