Not so transposons, am discussing about Bacteria called Pseudomonas aeruginosa, in which multiple pseudogenes were identified. but phages are incorporated.
Probably a result of functional redundancy of no longer required horizontally acquired genes in the large plastic/promiscuous genome of Pseudomonas. Pseudogenes accumulate in host-adapted salmonella, where their function needed to colonise multiple hosts or survive in a range of environments becomes redundant.