With DeFi, you can increase T because the aggregate value of transaction per delta time increases thanks to composability of money. In the traditional system, locking up money means buying an asset where that value then becomes illiquid (like buying shares of a stock, or a bond). However in DeFi, that same asset can be tokenized and used as liquidity as a tokenized collateral. For example, I can tokenize a TSLA share and then use that as collateral in a contract where I can get a yield. I could also pair TSLA with a stablecoin as a liquidity position (1:1 TSLA/USD) and tokenize the liquidity position which can then be used in other contracts.

The total aggerate value per unit time increases thanks to composability of contracts. You should download Metamask and use DeFi, it'll become clear what I'm talking about.

You want higher velocities of money because then that value is being put to work. When you have low velocities of money it means you have hoarding behavior which leads to deflation and a shrinking economy. With DeFi, the same value is more efficient than the traditional system because that value can be allocated more efficiently (i.e. higher yields thanks to tokenized positions and composable contracts), thus you get more bang for your buck so-to-speak.

Also, just having something like Uniswap with pooled liquidity means assets are more liquid, which also increases velocity of money. More liquidity = higher velocities of money. This is how you bank the unbanked, by giving everyone access to financial markets as long as they have an internet connection.

What you describe as "tokenization" exists in traditional finance, and has existed for ages. For example, money market funds invest funds in money market instruments and then fractional ownership of the fund (and therefore of the underlying investments) in the form of shares can be bought and sold in the market. In short, this is not a DeFi innovation.

"Liquidity" refers to the easiness with which an asset can be converted into money. For example, a share is less liquid than money (because money is the most liquid asset, by definition) but more liquid than a house, because shares are sold easier than houses. Shares and bonds tend to be quite liquid. For example, some government bonds are so liquid that are considered a "money equivalent". And "tokenizing" an asset doesn't necessarily makes it more liquid. Finally, shares and bonds are used as collateral all the time. In fact, any financial and non-financial asset can be used as collateral. For example, a mortgage is a loan that is secured by real estate, even though real estate is relatively illiquid. It still used as collateral.

With regards to the velocity of money, you're misinterpreting something called the Quantity Theory of Money. The velocity of money is linked to the level of economic output but it doesn't really make sense to try to influence the velocity of money through economic policy in order to control the level of economic activity, it doesn't work like that. Also the velocity of money isn't being limited by some bottleneck in the financial sector, and specifically isn't being limited by money not being "composable" enough, whatever that means. Your whole argument about the velocity of money just doesn't make any sense.

I think you have good intentions but clearly you don't know much about finance, and if you're interested in DeFi you should definitely learn a little bit about finance, because right now you don't quite seem to grasp even the most elementary of financial concepts. I'm telling you that in good faith, don't take it badly.