is ipad 6th gen outdated

Technically it is now “outdated”, but outdated does NOT mean obsolete.

Just discontinued and not avaible for sale on Apple's main website, any longer.

It is still available as a discounted and refurbished model on Apple's Refurbished & Clearance section of the Apple Website.

The new 2019 10.2 inch screen 7th gen iPad has replaced it, but the specs are still similar.

Only the screen size on the 7th gen iPad has changed, basically.

You can expect the 6th gen, 9.7 inch screen iPad to get another 3-4 years of iOS upgrades and updates from Apple.

Third party app developers will support that iPad even longer.

No. Apple just doesn't sell it anymore. Except for the refurbished units.

It will get iPadOS 13 which will be released on the 24th of September.