I would posit, that PDS migrated from the classic early 2000's model that we've seen e.g. with EU3, that is:
1. You get the game in a working condition. If something is broken, then you get a free patch.
2. Developer releases a DLC. It's big, probably size of three or four DLCs we get for EU4, albeit at higher price tag.
3. From now on patches are only for the owners of the said DLC.
4. New DLC, previous one required, patches only for newest version.
to a somewhat "Patreon style" type of financing. The DLCs are poly-centric i.e. like a menu-you choose what you want. Personally I consider it to be a very noble yet unsustainable approach. I would posit, that after some time, like a year or two, the DLCs should be made obligatory to receive new patches in exchange permitting full integration of features. Like said earlier, the estates are absolutely great as an idea, but they currently are a bit lacklustre and shallow.
The problem is, that with small, optional DLCs development model, they have to be like that. An optional feature, has to be, well, optional. That is a separate, non-integrated "closed garden". In long term EUIV with integrated estates and without cannot be both supported. Under current conditions a mid-size group called here earlier "hardcore fanboys" considers it to be a proof of attachment to support the PDS through DLC purchases, even though a big part of the money gets spent on the free content and patches available to all those, who do not participate in the ongoing development costs.
To give PDS its due merit, it does keep the player base big, much, much bigger than it would ever be under my proposed, classical development model. However, as PDS published own statics show, the grand strategy games are played mostly solo (Is it 85% playtime on average?), so I really do not fully understand, why care so much about the multiplayer fan base from purely commercial point of view?
Disclaimer: as a practically M&T mod-exclusive player I could do without any DLC. However being given how much the developers are accommodating the modding community I feel obliged to support the company. I don't use their products, but I do use their working hours a lot. In a perfect world, I could simply pledge an amount of cash every month which would go directly to enhance modding capabilities of the engine and script. In the meanwhile, the DLC have to suffice.
If somebody feels entitled to buying and playing the base game, then as an experience I would propose reverting to the last pre-DLC patch and compare it with what we have now.