There are more factors than that. How much will same day PC releases impact console sales? The piracy factor plays into this. It's much harder to pirate a console game then a PC game. So they will lose out to console+PC gamers who opt to pirate a copy of the game instead of buying it on either platform.
I guess my point is that console sales are not as important as they used to be. Only 20% of Sony's Playstation revenue nowadays is console hardware, and basically none of that is profit. Selling to their captive audience gives them at most 125 million potential customers to buy day one at full price. Throw in just Steam users and now you have 215 million potential full price customers. Yeah, you might have some piracy, but that is the cost of accessing a huge amount of additional gamers. And honestly, which person who pirates games is likely to buy it on any platform near launch for full price?
Also, development cost, as a like for like port makes no sense as the generation progresses. PC hardware outpaces the console side, so you run the risk of damaging the brand with subpar same day ports that aren't optimized to compete with other contemporary games on the PC side.
So, you can increase development cost to optimize for PC, but it incurs overhead on a project that isn't guaranteed success yet, which increases risk. Considering they make a lot of big budget games, that's a lot of risk of the game meets commercial failure.
This argument made sense in the days of PS3 and Xbox 360, but is almost nonsensical now. At this point both Sony and Microsoft consoles use PC grade CPU, GPU, and SSD with x86 software code. They are basically PCs in everything but name. These games are developed and tested on PC and the process of "porting" them to console is easier than it has been in any console generation. If you start putting out your games day and date on PC/Console there will be little difference between versions anyway.
By waiting for the sales to plateau, they can pick from the titles that have bonafide demand. Since the games are old by now, they can get away with ports that lack polish against contemporary PC titles, because it's understood to be a legacy title, so the comparison is made to the console version from the past, rather than the best and brightest on the PC at that time. They can devote a smaller team to handle the port as well, which lowers risk, should reception be lukewarm on PC.
But this makes no sense. By waiting until years later to port to PC all of the new game hype and your big initial advertising push is gone. Not only that, but you are going to have to discount your game faster as it is seen as a legacy title.
There are other factors, but it all depends from protecting the HW business. There's a lot of revenue that is tired directly to the HW. PS+ is an earner, and that service isn't going to fly on PC. Cannibalizing that to jump full force into PC swimming pool doesn't make a ton of sense. If they intend on maintaining the HW side of things, then same day releases just don't make sense. MS has never had the same success that Sony has had on the hardware side, so their interests are different. They see more value in services, so same day releases make more sense for them. That and Windows is their platform. They have a vested interest in furthering engagement with that platform. Sony going same day would move them into third party territory, which is the tricky business that sees even large firms like Bethesda being sold. Valve and Epic have avoided that by creating their own platforms in the form of storefronts, so I don't see Sony abandoning the rather lucrative platform they've spent decades building.
Again with the hardware, barely any profit is made on that. The only benefit is ecosystem lock-in, but it's still not super common for someone to have all platforms (PC+Console) unless they are hardcore, which is a minority of gamers.
When it comes to PS+, why the heck would a PC player ever have PS Plus, even if they do have a console???? You don't need PS+ for F2P games, which you probably play on PC anyway. If you are mostly a PC player then your third party multiplayer games are probably also going to be played on PC, so again no need for PS+. Sony first party have almost no great multiplayer games, so again, why PS+? The people subscribing to PS+ are the ones who play on console only, same with Xbox Live.
Overall, I think we will see Sony PC games get closer and closer to day and date releases as Sony gets a taste of strong PC sales.