Dude, no. That's the downtime section and basically says "hey, you should build a stronghold or make magic items." And you are ignoring that there are plenty of people who don't want to do that.
There is nothing in the PHB or branding for the game that tells people "ooh, this is great -- you're going to loot ancient tombs so you can BUILD A GUILDHALL." It's not what people are signing up for.
There is a resource that accumulates by doing Activity A that you cannot spend in aid of Activity A. The fact that the DMG says "here's Activities B, C and D you can use with that resource instead" is not good design. Telling someone they have to start a different style of play to use the resource is an admission by the designers that the resource has little relevance to Activity A.
DMs aren't bad DMs for not saying "sorry, dude, at this point, you're pretty much required to start spending that gold on all these activities in order to remain engaged with treasure as a motivational tool." In fact, I'd say that them acting that way would be a great example of being a crappy DM. If your players want to do Activity A (adventure and kill stuff), forcing them to do something they've expressed no interest in is a great way to be one of these ENWorld posters who bemoan their inability to hold a group together.
The fix for "what the hell do I do with all this damned gold" isn't more downtime activities, it's to dramatically reduce the amount of gold given out by default in the game unless your players express a desire to do all those downtime activities.