> once we as a species transition fully to lab grown meat

I wish... there are many obstacles to implementing that on the scale and timeline needed. I worry we don't have time to wait for that, while we already have plants that could sustain us completely and easily (82% of calories, 63% of proteins).

https://ourworldindata.org/land-use-diets

> it is simply less convenient than eating meat

Tradition, culture, convenience, taste. The only reasons.

> There really is no alternative currently that still satiates people's demands for the taste of meat

It's starting to change. Plant-based alternatives for meat (junk food) are getting better everyday (at least where I live).

In the last years came new bacon and sausages, which my SO refuses to eat because they're "too meat-like".