Like GB. What if Rodgers plays for another 3 seasons and stays healthy and plays well. Do you give Love that 5th year option not knowing what he is like on the field? In that case, you pretty much have too. What if he doesn't pan out in that 5th year, do you give up on him after just one season, or give him the tag just to see if he progresses. If he doesn't pan out, it sets them back because of the resources used to get him and grooming him for him for years.
Definitely is easier said than done. New England kept trying to find Brady's replacement and he outlasted them all and they were stuck with the situation where either they see what they had with Stidham or try strike lightning with Cam to stay competitive. Do the Saints really believe that Taysom Hill is a Franchise QB? What is TB plan after next season? Colts are going to going to be in a situation where they going to have to trade for a QB to extend their window.
Only 8 of 32 teams have a starting QB at the start of season that weren't drafted by them, not counting Alex Smith. Of those 8, only 3 of those QBs you could say there was long term plans(more than 2 years) for those QBs at the acquisition of them. Those are Brees, Jimmy G, and Cousins. Brady and Rivers were seen as a 1-2 year then retire move. Tannehill was supposed to be backup until Mariota flamed out. Cam was a salvage project/prove it deal at best. Bridgewater is seen as the bridge QB until they find the QB of future. Good QBs in their prime don't typically hit the market.