I never really notice my buying spree going upwards or downwards.
Do keep in mind, over time, your taste in games might become more specific.
Having had a taste of some genre of games and maybe having tried out more indie games, you might have a smaller selection of games which you really like.
That and the releases lately have also been a lot of indie games and games of smaller developers.
This also causes the potential good games to be drowned in the sea of other games that get released.
It happens a lot on platforms like Steam, but also on like appstores for your mobile phone for example.
And maybe there is a dip in good quality games lately, i am not entirely sure, but it could be.
Most of them get released near certain time periods in a year, everything between gets less big releases.
I am not entirely familiar with the big release periods, it's just an idea on why you feel like this.
And sometimes it is good to try something which might be interesting.
I guess that also ties in with your taste becoming more and more refined.
Over time you have tried some potentially interesting games and they turned out bad and now you might have this bad taste of that certain games for games that have similarities.
So like, maybe you are less inclined to try out new things.
I am just throwing ideas here though, there is a lot of reasons why you notice a lack of "good" Steam games.
Many will agree, many will disagree, it is all a matter of taste and above all opinion.
RAPID EDIT:
Additionally this could also tie in with the way games are now being developed and supported.
Games are now a lot more seen as a service, where a lot of people expect the developer to work on the game even after the initial release.
There is a lot to say about this, so i will not go into details, but it could be that the 'good' developers are just too busy working on their already existing products to match the public's demand.
