Having worked as Marketing manager and communications manager for more years than I care to mention, what I can say is that Trade shows, no matter what the industry are always one of the biggest discussions and expenditure. ....
Launching at trade shows today is a risky business and it's why many companies don't go down this route any more.
For one, you have way less control of the messaging and mapping you are trying to get across, in fact, months of preparation can go awry through just one comment, photo, video posted to social media. Sony holding their own conference allows them to control the narrative as tightly as is possible these days. It's up to them if they invite the press and who from the press they invite, this is much easier to control than a trade show. Obviously, social media is another matter but if they pack the hall with PS5 fans, they will control the narrative. The only negative on these types of shows is that the press hates them. Normally one channel is picked as the major outlet and there's generally a lack of questioning and critique involved, which to be fair is exactly what Sony would want.