The implication of "rain on your wedding day" is that your wedding day is something you plan out extensively, trying to create some perfect event. And yet it can still be thwarted by weather. Obviously it takes some interpretation since it's a situation compressed into a 1-line song lyric but yes it can (and should, given that the song is called "ironic") be read as an example of cosmic irony.
Apple and Google will never choose to integrate Microsoft's services or products willingly.
It would have been more surprising if they decided to depend on Microsoft.
Bing is irrelevant, VSCode might top in some places, but it is cursor and Claude that people are reaching for, VS is really only used by people like myself that still care about Windows development or console SDKs, otherwise even for .NET people are switching to Rider.
What is the irony? Microsoft integrated copilot in Vscode, bing, etc. Apple is integrating claude in Xcode, Jetbrains has their own AI.
Microsoft moved first with putting AI into their products then other companies put other AI into their products. Nothing about this seems ironic or in any way surprising.