It could, but remember you are only buying the Liam's that are presently on the market. The moment you issued your highest priced Liam, you would have other sellers dropping their Liam's as well.
In truth the only way to permanently affect the price of a character is to impact the supply. You would be doing this by holding far more Liam's than you could ever need, but you would also want to ensure you only auctioned a limited quantity at a time. Might even be best to start offering to buy other players' Liams before you start clearing the market.
Control Supply, Control Price, principles of a monopoly. There is still price elasticity to factor in. Liam isn't the most highly demanded card on the market (Cortez may take that cake, presently), so there is still a price people will only be willing to pay. If the price you set is higher than the market is willing to pay, you will be forced to lower price.
It is definitely something to think about, but not Liam. Maybe on a more valuable card that is still semi attainable with a 10,000 clint price point. You may be able to drive the price up to 20 or even 30,000 this way. But it would take much more than 70,000 to do it.
It's called "spiking" by spiking your spiking there price.. most of them times it's a complete FAIL unless you have money to blow.. you have to do it when there are small amounts of cards and you should do it with a friend or a Guild.. Like There's a few Business guilds like City of Business they spiked Rolph 's price from 3K to 10K in a month now it's permenately like that.. Well for the mean while.. but, the thing is.. there wasn't alot of rolph because he was banned from elo so lots of people sold him off when they didn't need him and alot of people dont play ghiest in Survivor (some not many) and alot of people dont play them in Daily Tournaments so.. he wasn't getting played much and the only hope of him staying a strong price was him being CR speculated so.. the COB just basically spiked his price and stayed constant with it for a month and now they are reaping rewards.. but, one guy has over 1000+ Rolph 's being worth a pretty penny so now he has to trade.. and sell cautiously because if he just loads them off to the market he will crash his price.. Well basically what I'm saying
1.) you have to have loads of cash (the cheaper the card the more copies it has...)
2.) try having a partner(s) to help you so that you wont be the only one watching and 4 eyes are better then 2
3.) stay consistant and try not to give up if your motivated to make profit
4.) make extra sure you do your research on the card before you do it so you won't lose out