EDIT: Apologies. Updated with a link to what gorhill REALLY said:
Manifest v2 uBO will not be automatically replaced by Manifest v3 uBOL[ight]. uBOL is too different from uBO for it to silently replace uBO – you will have to explicitly make a choice as to which extension should replace uBO according to your own prerogatives.
Ultimately whether uBOL is an acceptable alternative to uBO is up to you, it’s not a choice that will be made for you.
Will development of uBO continue? Yes, there are other browsers which are not deprecating Manifest v2, e.g. Firefox.
Tech people are niche but over time we will pre-install what we consider “good” on our grandmas, dads, moms, friends, etc… PCs
The older generation demographic continues to shrink, while it seems the great majority of Gen Z and A are perfectly happy to use whatever ecosystem is built into their device. I’m not saying that people shouldn’t want better software, merely being realistic about the choices of populations.