Just speculation on my part, same as everyone else on this topic, but here goes.
I think there are three factors at play here. In no particular order ;
1. The continuing uncertainty over whether Guehi and Eze are staying. I've mentioned before that Guehi wants to be starting games and that's not guaranteed while Konate remains at Liverpool. Konate is also in the last year of his contract. From Press reports ( I know ) it seems he's planning to run down his contract and walk away on a free transfer next summer. If that's the case, Guehi is highly unlikely to move.
As for Arsenal/Eze, Arsenal look to be hoping that Palace drop the price from the quoted release clause of £67m. Unless the player agitates for this move I can't see it happening nor can I envisage Parish reducing the asking price. So in the Media, all we read about is both players leaving and links to possible replacements - Diomande being an example. We can't afford to sign that player and then Guehi doesn't move.
2. Textor's exit - Johnson's arrival. Possible financial impact to the club while this transaction was in flight - ie. Palace were not able to fund / borrow significant amounts to buy players.
3. The UEFA situation. Not going to rehash all that again.
Now let's look at what others - mainly in what I consider to be our peer group, have been doing ;
Aston Villa - 3 players in at a cost of £5.9m
Bournemouth - 2 in - and they've sold players that will surely leave them weaker this coming season
Brentford - 5 in - funded by the sale of key players
Brighton - 6 in - funded by sales of Joao Pedro, Estupinan, Adingra
Burnley - 10 in - quantity but lacking quality imo
Everton - 4 in - Moyes complaining similar to Glasner
Fulham - 1 in
Leeds - 7 in
Notts Forest - 2 in
Sunderland - 6 in
West Ham - 3 in - one of those is Todibo, loaned out last season but WH had an obligation to buy
Wolves - 3 in
So, the likes of Liverpool, Arsenal, City and Chelsea spending big. Man U and Spurs have spent money too. Newcastle are feeling the impact of the Isak situation.
So while wholeheartedly agreeing that it's preferable to get players signed asap in the transfer window and get them integrated into the squad in pre season, the fact is that it's not that simple for a club like ours. Parish may have promised to avoid a repeat of last summers window but he's not in total control over the transfer market. Nor could he have foreseen some of the events of the last few months.
He has history of leaving business late but I don't think it was his intention to do that this time. Glasner is an intelligent guy so I would expect him to understand that there are mitigating circumstances at play here. Yes, he's voiced his frustration publicly and yes, he's fallen out with owners before after winning a trophy. But there's also no media story if he'd said he was happy with what he's got. We'll see !
Apologies for the length of this post.