Phrase for making an unnecessary purchase before engaging in an activity

Is there an expression or phrase to describe the misguided behavior of believing that purchasing an item relating to an activity you wish to pursue will give you the motivation to actually engage in that activity?

For example, a person who never jogs outdoors purchases an expensive treadmill, thinking that purchase will be the impetus to make them "a jogger" rather than simply going for a run outside and maybe buying a treadmill sometime in the future, after they've stuck with it for a while.

Or a person who never bakes will purchase a top-of-the-line stand-mixer, believing they'll begin baking once they own the proper tools, even though they could have baked a cake with the equipment they already owned.

The implication here is that this is a false premise; if you don't run or bake now, you're unlikely to make it a regular habit just because bought a fun new toy. You've made an unnecessary purchase and you still aren't engaging in the activity in question.

Solution 1:

This is an example of wishful thinking / wishful buying

The attribution of reality to what one wishes to be true or the tenuous justification of what one wants to believe m-w

In modern use in weaker sense: expressing or indicative of a wish; chiefly in wishful thinking, thinking, esp. belief or expectation, that is influenced by one's wishes to the extent that relevant (consciously) known facts are (subconsciously) ignored or distorted; also as adj.; so wishful thinker. OED

He [sc. a prisoner] hoarded these glimpses of past happiness, rationing his wishful reminiscing to half an hour a day.

Joseph Pilates once said, “Physical fitness can neither be achieved by wishful thinking, not outright purchase.” Brian Richey; Back Exercise: Stabilize, Mobilize, and Reduce Pain

Wishful thinking doesn't work and may be dangerous.
Permit me to illustrate the point: I would love to flap my arms and fly to the moon. And sometimes I would like it to rain beer. Those things are not possible. Bernard M. Patten Truth, Knowledge, Or Just Plain Bull

For some items we buy but never use, we sometimes say "It's just a glorified X." For example, with regard to exercise equipment:

"Take it away: why fitness machines turn into clothes hangers"

Some are impulse purchases, while although others are planned, researched purchases.

Wishful buying seems to be rare, but I see no reason not to use it since wishful fits the definition.

The availability of paperbacks has made a difference in the buying of books; who can say if it has made an impact upon reading. I know some people who do wishful buying but never get to reading. Wilson Library Bulletin, Vol.36, p.239

Yet a case can be made out for the hire-purchase of necessities, as distinct from the wishful buying of non-essential luxuries R. Dallas Brett; Usury in Britain.

Solution 2:

Technically, I think it's a (failed) precommitment mechanism.

Aspirational purchase: A purchase made (often clothing) that isn’t something someone would typically buy, but represent a place or way of life they aspire to be where they would buy things like that all the time. (From Rice.edu, listed as a neologism.)

Somewhat generically: idealistic (purchase) or overly optimistic (purchase).