So it requires verifiable facts to hold as certain that this product has a budget and that in a case of planned MU, a part of this budget is allocated to the developpment of the MU features.

There is a confusion on the burden of the proof. In this process, the effort of collecting evidences is balanced by a counterpart: providing evidences of will be met by something valuable in return.

It is not the case here.

People who prefer to think that this product developpment is not supported by a budget and in a case of planned MU features are not allocated a part of this non existent budget are welcomed to believe it as much as they desire it.

No. MU and SP exclude each other to some extent.

Board games used to be MU. Computer gaming has done a lot for SP gaming and as a consequence, board games came to introduce SP more and more.

It is common for a board game to depict itself as playable by one to 4,5 or 6 players etc
Following that, it is also grown common for board gamers to enquire whether a game is SP or MU and when it is MU, to enquire on the number of players meant to play it.

SP depends exclusively on one player.
MU depends exclusively on a fixed number of players.

It is not possible to add/remove players at will.

SP is more and more given up on because it does not support the new direction of social time.

More and more, devs offer their customers a virtual place to chill out with friends or acquaintances.
It is a virtual substitute to the swing hung to the tree where people are used to gathered.

It shifts the experience from the product to the group of people experiencing it: it is an enjoyable experience thanks to the group of friends. The product is an excuse to hang out together, to spend time together.

SP is intimate experience, needs AI and can be discussed afterwards.
MP is searching for heard acceptance or mass hysteria, doesn't need AI and needs no discussing later.
Streaming is false presentation of products on par with advertisments that lie about products' efficiency and needs to be declared illegal.

No, the phrase "singleplayer multiplayer" would be an oxymoron, the idea that adding multiplayer to a singleplayer game could bring benefits to the singleplayer experience is not. For example, Luckyday suggested a couple of pages back that by making it multiplayer, the code would likely have to be more stable and less hacky, the gameplay better balanced, etc. That's a perfectly reasonable argument.

Tomron thinks that devoting resources to multiplayer rarely, if ever, helps the SP game. You said this was not accurate, and then cited examples of how multiplayer can also be fun, which seems not to follow.

I certainly don't recognize myself in that description.

pibbur who wishes for a more sober discussion of playing "paradigms".

Streamers misrepresent any product that is not meant for them.
Many products are increasingly meant for streamers. Streamers have it correct when they play such products.

Does not prevent players from laudating products that were meant for streamers first.

Reasonable by this site's appreciation.

Balancing requires to take into account all the elements.
A MU gameplay wealth stems from the interactions that are set between players, which are determined as a fixed number.

Despite featuring so many self proclaimed supporters of party based products, stating that making a product MU leads to better balance.
It must be believed that in a party based product, the gameplay is balanced regardless of the number of party members. One, two, three, four, the gameplay is balanced. A party features a tank, a DPS, a healer, the gameplay is balanced for any composition.

And MU gameplay is more demanding than those simple low level interactions that usually exist in party based SP stuff.

Adding, withdrawing at will is not given.

As an imperative, MU products set a time expectation for players to play together. It is mandatory.

Such constraint does not exist in SP: a player plays one hour or ten hours if wanted. A player hops out of the experience at will.

MU does not add on that. Players start to play together, one must leave. The other must leave, even when wanting to keep playing. Or keeps playing at the expense of the one who left first.

SP allows a player to organize the experience as wanted. MU does not.